Problem:
 Score : 500 points    Problem Statement There are N towns numbered 1 to N and M roads. The i -th road connects Town A_i and Town B_i bidirectionally and has a length of C_i .  Takahashi will travel between these towns by car, passing through these roads. The fuel tank of his car can contain at most L liters of fuel, and one liter of fuel is consumed for each unit distance traveled. When visiting a town while traveling, he can full the tank (or choose not to do so). Travel that results in the tank becoming empty halfway on the road cannot be done.  Process the following Q queries:   The tank is now full. Find the minimum number of times he needs to full his tank while traveling from Town s_i to Town t_i . If Town t_i is unreachable, print -1 .       Constraints  All values in input are integers.  2 \leq N \leq 300  0 \leq M \leq \frac{N(N-1)}{2}  1 \leq L \leq 10^9  1 \leq A_i, B_i \leq N  A_i \neq B_i  \left(A_i, B_i\right) \neq \left(A_j, B_j\right) (if i \neq j )  \left(A_i, B_i\right) \neq \left(B_j, A_j\right) (if i \neq j )  1 \leq C_i \leq 10^9  1 \leq Q \leq N\left(N-1\right)  1 \leq s_i, t_i \leq N  s_i \neq t_i  \left(s_i, t_i\right) \neq \left(s_j, t_j\right) (if i \neq j )         Input Input is given from Standard Input in the following format:  N  M  L  A_1  B_1  C_1  :  A_M  B_M  C_M  Q  s_1  t_1  :  s_Q  t_Q       Output Print Q lines.  The i -th line should contain the minimum number of times the tank needs to be fulled while traveling from Town s_i to Town t_i . If Town t_i is unreachable, the line should contain -1 instead.        Sample Input 1 3 2 5
1 2 3
2 3 3
2
3 2
1 3      Sample Output 1 0
1  To travel from Town 3 to Town 2 , we can use the second road to reach Town 2 without fueling the tank on the way.  To travel from Town 1 to Town 3 , we can first use the first road to get to Town 2 , full the tank, and use the second road to reach Town 3 .       Sample Input 2 4 0 1
1
2 1      Sample Output 2 -1  There may be no road at all.       Sample Input 3 5 4 4
1 2 2
2 3 2
3 4 3
4 5 2
20
2 1
3 1
4 1
5 1
1 2
3 2
4 2
5 2
1 3
2 3
4 3
5 3
1 4
2 4
3 4
5 4
1 5
2 5
3 5
4 5      Sample Output 3 0
0
1
2
0
0
1
2
0
0
0
1
1
1
0
0
2
2
1
0

Solution (Python):
from scipy.sparse.csgraph import floyd_warshall
import numpy as np

N, M, L = map(int, input().split())
inf = 10**9 + 1
dist = [[inf] * N for i in range(N)]
for i in range(M):
    A, B, C = map(int, input().split())
    dist[A-1][B-1] = dist[B-1][A-1] = C

dist = floyd_warshall(dist, directed=False)
dist = np.where(dist <= L, 1, inf)
dist = floyd_warshall(dist, directed=False)
dist = np.where(dist < inf, dist-1, -1)

Q = int(input())
for i in range(Q):
    s, t = map(int, input().split())
    print(int(dist[s-1, t-1]))

Solution (Python):

def main():
    import sys
    input = sys.stdin.readline  
    N, M, L = map(int, input().split())
    
    d = [[10 ** 12] * N for _ in range(N)]  
    
    for i in range(M):
        a, b, c = map(int, input().split())
        if L >= c: 
            d[a - 1][b - 1] = d[b - 1][a - 1] = c
    for i in range(N):
        d[i][i] = 0  
    
    
    
    for k in range(N):
        for i in range(N):
            for j in range(N):
                d[i][j] = min(d[i][k] + d[k][j], d[i][j])
    
    
    edge = [[10 ** 12] * N for _ in range(N)]
    for i in range(N):
        for j in range(N):
            if d[i][j] <= L:
                edge[i][j] = 1
    
    
    for k in range(N):
        for i in range(N):
            for j in range(N):
                edge[i][j] = min(edge[i][k] + edge[k][j], edge[i][j])
    
    
    Q = int(input())
    for _ in range(Q):
        s, t = map(int, input().split())
        if edge[s - 1][t - 1] >= 10 ** 12:
            print(-1)
        else:
            print(edge[s - 1][t - 1] - 1)  
    
if __name__ == "__main__":
    main()

Solution (Python):
N, M, L = map(int, input().split())
INF = 10**12
dp = [[INF]*N for i in range(N)]
fp = [[INF]*N for i in range(N)]
for i in range(N):
  dp[i][i]=0
  fp[i][i]=0
k = [[0]*N for i in range(N)]
for i in range(M):
  a, b, c = map(int, input().split())
  dp[a-1][b-1] = c
  dp[b-1][a-1] = c

for i in range(N):
  for j in range(N):
    for h in range(N):
      dp[j][h] = min(dp[j][h], dp[j][i]+dp[i][h])

for j in range(N):
  for h in range(N):
    if dp[j][h]<=L:
      fp[j][h] = 1
for i in range(N):
  for j in range(N):
    for h in range(N):
      fp[j][h] = min(fp[j][h], fp[j][i]+fp[i][h])
Q = int(input())
for i in range(Q):
  s, t = map(int, input().split())
  s = s-1
  t = t-1
  if fp[s][t]==INF:
    print(-1)
  else:
    print(fp[s][t]-1)

Solution (Python):
from scipy.sparse.csgraph import floyd_warshall

n, m, l = map(int, input().split())
inf = 10**12
d = [[inf for i in range(n)] for i in range(n)] 

for i in range(m):
    x,y,z = map(int,input().split())
    d[x-1][y-1] = z
    d[y-1][x-1] = z
for i in range(n):
    d[i][i] = 0 
dd = floyd_warshall(d)
ddd = [[inf for i in range(n)] for i in range(n)]
for i in range(n):
  for j in range(n):
    if dd[i][j] <= l:
      ddd[i][j] = 1
dddd =floyd_warshall(ddd)
q = int(input())
for i in range(q):
  s, t = map(int, input().split())
  if dddd[s-1][t-1] == inf:
    print(-1)
  else:
    print(int(dddd[s-1][t-1]-1))

Solution (Python):
N,M,L = map(int,input().split())
ABC = [list(map(int,input().split())) for _ in range(M)]
Q = int(input())

class WarshallFloyd:
    def __init__(self,n):
        self.n = n
        self.inf = 100000000000000
        self.d = [[self.inf for _ in range(n)] for _ in range(n)]
        for i in range(self.n):
            self.d[i][i] = 0
    def register(self,v1,v2,l,multiple=True):
        self.d[v1][v2] = l
        if multiple:
            self.d[v2][v1] = l
    
    def solve(self):
        for i in range(self.n):
            for j in range(self.n):
                for k in range(self.n):
                    self.d[j][k] = min(self.d[j][k],self.d[j][i]+self.d[i][k])
        return self.d

W = WarshallFloyd(N)
for a,b,c in ABC:
    W.register(a-1,b-1,c)
D = W.solve()

WL = WarshallFloyd(N)
for i in range(N):
    for j in range(N):
        if D[i][j] <= L and i != j:
            WL.register(i,j,1)
DL = WL.solve()
ST = [list(map(int,input().split())) for _ in range(Q)]
for i in range(Q):
    s,t = ST[i]
    transition = DL[s-1][t-1]
    if transition == 100000000000000:
        print(-1)
    else:
        print(transition-1)

Solution (Python):
INF=10**15
N,M,L=map(int,input().split())
d=[[INF for i in range(N)] for j in range(N)]
d1=[[INF for i in range(N)] for j in range(N)]
for i in range(N):
    d[i][i]=0
for m in range(M):
    A,B,C=map(int,input().split())
    d[A-1][B-1]=C
    d[B-1][A-1]=C

for k in range(N):
    for i in range(N):
        for j in range(N):
            d[i][j]=min(d[i][j],d[i][k]+d[k][j])
for i in range(N):
        for j in range(N):
            if i!=j and d[i][j]<=L:
                d1[i][j]=1
                d1[j][i]=1
for k in range(N):
    for i in range(N):
        for j in range(N):
            d1[i][j]=min(d1[i][j],d1[i][k]+d1[k][j])

Q=int(input())
for _ in range(Q):
    s,t=map(int,input().split())
    dis=d1[s-1][t-1]
    if dis==INF:
        print(-1)
    else:
        print(dis-1)

Solution (Python):
import math
import sys
input = sys.stdin.readline

N, M, L = list(map(int, input().split()))

T = []
T1 = []
for _ in range(N):
    T.append([float("inf")] * N)
    T1.append([float("inf")] * N)
for n in range(N):
    T[n][n] = 0
    T1[n][n] = 0

for _ in range(M):
    A, B, C = list(map(int, input().split()))
    A -= 1
    B -= 1
    T[A][B] = C
    T[B][A] = C

for k in range(N):
    for i in range(N):
        for j in range(N):
            if T[i][j] > T[i][k] + T[k][j]:
                T[i][j] = T[i][k] + T[k][j]

for j in range(N):
    for i in range(N):
        if i == j:
            continue
        if T[j][i] <= L:
            T1[j][i] = 1
            T1[i][j] = 1

for k in range(N):
    for i in range(N):
        for j in range(N):
            if T1[i][j] > T1[i][k] + T1[k][j]:
                T1[i][j] = T1[i][k] + T1[k][j]

Q = int(input())
for _ in range(Q):
    S, G = list(map(int, input().split()))
    if math.isinf(T1[S-1][G-1]):
        print(-1)
    else:
        print(T1[S-1][G-1]-1)

Solution (Python):
import sys
input = sys.stdin.readline


def calc(N, g):
    for k in range(N):
        for i in range(N):
            for j in range(N):
                g[i][j] = min(g[i][j], g[i][k] + g[k][j])


def main():
    N, M, L = map(int, input().split())
    adj = [{} for _ in range(N)]
    for _ in range(M):
        A, B, C = map(int, input().split())
        adj[A-1][B-1] = C
        adj[B-1][A-1] = C
    dst = [[float("inf")] * N for _ in range(N)]
    for i in range(N):
        dst[i][i] = 0
        for j in adj[i]:
            dst[i][j] = adj[i][j]
    calc(N, dst)
    ans = [[float("inf")] * N for _ in range(N)]
    for i in range(N):
        ans[i][i] = 0
        for j in range(i+1, N):
            if dst[i][j] <= L:
                ans[i][j] = 1
                ans[j][i] = 1
    calc(N, ans)
    Q = int(input())
    for _ in range(Q):
        s, t = map(int, input().split())
        x = ans[s-1][t-1]
        print(-1 if x == float("inf") else x-1)


if __name__ == "__main__":
    main()

Solution (Python):



n, m, l = map(int, input().split())

def warshall_floyd(dp):
    for k in range(n):
        for i in range(n):
            for j in range(n):
                dp[i][j] = min(dp[i][j] , dp[i][k] + dp[k][j])
    return dp

dp = [[float('inf')]*n for _ in range(n)]

for _ in range(m):
    a, b, c = map(int,input().split())
    dp[a-1][b-1] = dp[b-1][a-1] = c

for i in range(n):
    dp[i][i] = 0

dp = warshall_floyd(dp)

dp2 = [[float('inf')]*n for _ in range(n)]

for i in range(n):
    for j in range(n):
        if dp[i][j] <= l:
            dp2[i][j] = 1
    dp2[i][i] = 0
dp2 = warshall_floyd(dp2)

q = int(input())

ans = [0]*q
for i in range(q):
    s, t = map(int,input().split())
    tmp = dp2[s-1][t-1]
    ans[i] = -1 if tmp == float('inf') else tmp - 1

print(*ans, sep='\n')

Solution (Python):
import sys
input = sys.stdin.readline

n, m, l = map(int, input().split())

def warshall_floyd(dp):
    for k in range(n):
        for i in range(n):
            for j in range(n):
                dp[i][j] = min(dp[i][j] , dp[i][k] + dp[k][j])
    return dp

dp = [[float('inf')]*n for _ in range(n)]

for _ in range(m):
    a, b, c = map(int,input().split())
    dp[a-1][b-1] = dp[b-1][a-1] = c

for i in range(n):
    dp[i][i] = 0

dp = warshall_floyd(dp)

dp2 = [[float('inf')]*n for _ in range(n)]

for i in range(n):
    for j in range(n):
        if dp[i][j] <= l:
            dp2[i][j] = 1
    dp2[i][i] = 0
dp2 = warshall_floyd(dp2)

q = int(input())

ans = [0]*q
for i in range(q):
    s, t = map(int,input().split())
    tmp = dp2[s-1][t-1]
    ans[i] = -1 if tmp == float('inf') else tmp - 1

print(*ans, sep='\n')

Solution (Python):
from scipy.sparse.csgraph import floyd_warshall
import numpy as np

N, M, L = map(int, input().split())
graph = np.array([[0 if i == j else float("inf")
                   for i in range(N)] for j in range(N)])
graph2 = np.array([[0 if i == j else float("inf")
                   for i in range(N)] for j in range(N)])


for _ in range(M):
    a, b, c = map(int, input().split())
    graph[a - 1][b - 1] = c
    graph[b - 1][a - 1] = c
dist = floyd_warshall(graph)

graph2[(dist <= L) & (dist != 0)] = 1
dist2 = floyd_warshall(graph2)
dist2[dist2 == float("inf")] = 0

Q = int(input())
for _ in range(Q):
    s, t = map(int, input().split())
    print(int(dist2[s - 1, t - 1]) - 1)

Solution (Python):
import sys
input = sys.stdin.readline

n, m, l = map(int, input().split())
INF = float("inf")

def warshall_floyd(d, n):
    for k in range(n):
        for i in range(n):
            for j in range(n):
                d[i][j] = min(d[i][j], d[i][k] + d[k][j])
    return d

d = [[INF] * n for _ in range(n)]
for i in range(n):
    d[i][i] = 0
for i in range(m):
    a, b, c = map(int, input().split())
    d[a - 1][b - 1] = c
    d[b - 1][a - 1] = c
d = warshall_floyd(d, n)

d2 = [[INF] * n for _ in range(n)]
for i in range(n):
    for j in range(n):
        if d[i][j] <= l:
            d2[i][j] = 1
    d2[i][i] = 0
d2 = warshall_floyd(d2, n)

q = int(input())
for _ in range(q):
    s, t = map(int, input().split())
    res = d2[s - 1][t - 1]
    print(-1 if res == INF else res - 1)

Solution (Python):
def warshall_floyd(n,d):
    
    for k in range(n):
        for i in range(n):
            for j in range(n):
                d[i][j] = min(d[i][j],d[i][k] + d[k][j])
    return d

import sys
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))
mod = 10**9 + 7
inf = float('inf')
ans = int(0)

N, M, L = LI()
d = [[float("inf") for i in range(N)] for i in range(N)]

for i in range(M):
    x,y,z = map(int,input().split())
    d[x-1][y-1] = z
    d[y-1][x-1] = z
for i in range(N):
    d[i][i] = 0 

cur = warshall_floyd(N,d)
newD = [[float("inf") for i in range(N)] for i in range(N)]
for i in range(N):
    for l,j in enumerate(cur[i]):
        if j<=L:
            newD[i][l] = 1
            newD[l][i]

ansC = warshall_floyd(N,newD)

Q = I()
for i in range(Q):
    s, t = LI()
    ans = ansC[s-1][t-1]-1
    if ans==inf:
        ans = -1
    print(ans)

Solution (Python):
import sys
import copy

N, M, L = list(map(int, sys.stdin.readline().strip().split(" ")))
INF = 10**10

def warshall_floyd(g_mat):
    dp = copy.copy(g_mat)
    
    for k in range(N):
        for i in range(N):
            for j in range(N):
                dp[i][j] = min(dp[i][j], dp[i][k]+dp[k][j])
    return dp

graph = [[INF for _ in range(N)] for _ in range(N)]

for _ in range(M):
    a, b, c = list(map(int, sys.stdin.readline().strip().split(" ")))
    graph[a-1][b-1] = c
    graph[b-1][a-1] = c

dist_graph = warshall_floyd(graph)
bool_graph = [[INF for _ in range(N)] for _ in range(N)]

for i in range(N):
    for j in range(N):
        if dist_graph[i][j] <= L:
            bool_graph[i][j] = 1

ans_graph = warshall_floyd(bool_graph)

Q = int(sys.stdin.readline().strip())
for _ in range(Q):
    s, t = list(map(int, sys.stdin.readline().strip().split(" ")))
    ans = ans_graph[s-1][t-1]
    print(ans-1 if ans != INF else -1)

Solution (Python):
import sys
import numpy as np
from scipy.sparse import*
F = csgraph.floyd_warshall
CSR = csr_matrix
input = sys.stdin.readline

n,m,l = map(int,input().split())
cost = [[0]*n for i in range(n)]
for i in range(m):
  a,b,c = map(int,input().split())
  cost[a-1][b-1] = c
  cost[b-1][a-1] = c  

Cost = F(CSR(cost))
Cost = F(CSR(np.where((0<Cost)&(Cost<=l),1,0)))

q = int(input())
for i in range(q):
  s,t = map(int,input().split())
  print(-1 if np.isinf(Cost[s-1][t-1]) else int(Cost[s-1][t-1])-1)

Solution (Python):
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import numpy as np
from scipy.sparse.csgraph import floyd_warshall
from scipy.sparse import csr_matrix

INF = 10**12
N, M, L = map(int, readline().split())

ABCQST = np.array(read().split(), dtype=np.int64)
ABC = ABCQST[:3*M]
A = ABC[::3]; B = ABC[1::3]; C = ABC[2::3]

Q = ABCQST[3*M]

ST = ABCQST[3*M + 1:]
S = ST[::2]; T = ST[1::2]

graph = csr_matrix((C, (A, B)), (N + 1, N + 1))
d = floyd_warshall(graph, directed=False)

d[d <= L] = 1
d[d > L] = INF

d = floyd_warshall(d, directed=False).astype(int)
d[d == INF] = 0

d -= 1
print('\n'.join(d.astype(str)[S, T]))

Solution (Python):
import numpy as np
from scipy.sparse.csgraph import floyd_warshall
from scipy.sparse import csr_matrix
INF = 10**12
N, M, L = map(int, input().split())

A = []; B = []; C = []
for i in range(M):
    a, b, c = map(int, input().split())
    A.append(a - 1); B.append(b - 1); C.append(c)
A = np.array(A); B = np.array(B); C = np.array(C)

graph = csr_matrix((C, (A, B)), (N, N))
d = floyd_warshall(graph, directed=False)

d[d <= L] = 1
d[d > L] = INF

d = floyd_warshall(d, directed=False)

Q = int(input())
for i in range(Q):
    s, t = map(int, input().split())
    if d[s - 1][t - 1] != INF:
        print(int(d[s - 1][t - 1]) - 1)
    else:
        print(- 1)

Solution (Python):
from sys import setrecursionlimit as SRL, stdin
inf = 10**15
SRL(10 ** 7)
rd = stdin.readline
rrd = lambda: map(int, rd().strip().split())

n, m, l = rrd()
dis = [[inf] * 305 for _i in range(305)]
need = [[inf] * 305 for _i in range(305)]
for i in range(n):
    dis[i][i] = 0
for i in range(m):
    a, b, c = rrd()
    dis[a][b] = c
    dis[b][a] = c

for k in range(1, n + 1):
    for i in range(1, n + 1):
        for j in range(1, n + 1):
            dis[i][j] = min(dis[i][j], dis[i][k] + dis[k][j])

for i in range(1, n + 1):
    for j in range(1, n + 1):
        if i == j:
            need[i][j] = 0
        elif dis[i][j] <= l:
            need[i][j] = 1

for k in range(1, n + 1):
    for i in range(1, n + 1):
        for j in range(1, n + 1):
            need[i][j] = min(need[i][j], need[i][k] + need[k][j])
q = int(input())

while q:
    s, t = rrd()
    if need[s][t] < inf:
        print(need[s][t]-1)
    else:
        print(-1)
    q -= 1

Solution (Python):
import math
import sys
MAX_INT = int(10e10)
MIN_INT = -MAX_INT
mod = 1000000007
sys.setrecursionlimit(1000000)
def IL(): return list(map(int,input().split()))
def SL(): return input().split()
def I(): return int(sys.stdin.readline())
def S(): return input()

N, M, L = IL()
abc = [IL() for _ in range(M)]
Q = I()
q = [IL() for _ in range(Q)]

dp1 = [[MAX_INT]*N for _ in range(N)]
for a, b, c in abc:
  dp1[a - 1][b - 1] = c
  dp1[b - 1][a - 1] = c

for k in range(N):
  for i in range(N):
    for j in range(N):
      if i == j:
        dp1[i][j] = 0
      else:
        dp1[i][j] = min(dp1[i][j], dp1[i][k] + dp1[k][j])

dp2 = [[MAX_INT]*N for _ in range(N)]
for i in range(N):
  for j in range(N):
    if dp1[i][j] <= L:
      dp2[i][j] = 1

for k in range(N):
  for i in range(N):
    for j in range(N):
      if i == j:
        dp2[i][j] = 0
      else:
        dp2[i][j] = min(dp2[i][j], dp2[i][k] + dp2[k][j])

for s, t in q:
  if dp2[s - 1][t - 1] == MAX_INT:
    print(-1)
  else:
    print(dp2[s - 1][t - 1] - 1)

Solution (Python):

from collections import defaultdict,deque
from heapq import heappush, heappop
from bisect import bisect_left, bisect_right
import sys, random, itertools, math
sys.setrecursionlimit(10**5)
input = sys.stdin.readline
sqrt = math.sqrt
def LI(): return list(map(int, input().split()))
def LF(): return list(map(float, input().split()))
def LI_(): return list(map(lambda x: int(x)-1, input().split()))
def II(): return int(input())
def IF(): return float(input())
def LS(): return list(map(list, input().split()))
def S(): return list(input().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')


def A():
    return


def B():
    return


def C():
    return


def D():
    return


def E():
    n, m, l = LI()
    dist = [[inf] * n for i in range(n)]

    for _ in range(m):
        a, b, c = LI_()
        c += 1
        if c > l:
            continue
        dist[a][b] = c
        dist[b][a] = c

    supply = [[n] * n for i in range(n)]
    for k in range(n):
        distk = dist[k]
        for i in range(n):
            if i == k:
                continue
            disti = dist[i]
            distik = dist[i][k]
            for j in range(i + 1, n):
                if distik + distk[j] < disti[j]:
                    disti[j] = distik + distk[j]
                    dist[j][i] = disti[j]

    lis = [[] for i in range(n)]
    for i in range(n):
        for j in range(i + 1, n):
            if dist[i][j] <= l:
                supply[i][j] = 0
                supply[j][i] = 0
                lis[i].append(j)
                lis[j].append(i)

    for i in range(n):
        q = []
        for k in lis[i]:
            heappush(q, (0, k))
        supplyi = supply[i]

        while q:
            time, p = heappop(q)
            for k in lis[p]:
                if supplyi[k] > time + 1:
                    supplyi[k] = time + 1
                    heappush(q, (time + 1, k))

    q = II()
    for _ in range(q):
        s, t = LI_()
        if dist[s][t] == inf:
            print(-1)
            continue
        else:
            print(supply[s][t])
    return



def F():
    return


def G():
    return


def H():
    return


if __name__ == '__main__':
    E()

Solution (Python):

from collections import defaultdict,deque
from heapq import heappush, heappop
from bisect import bisect_left, bisect_right
import sys, random, itertools, math
sys.setrecursionlimit(10**5)
input = sys.stdin.readline
sqrt = math.sqrt
def LI(): return list(map(int, input().split()))
def LF(): return list(map(float, input().split()))
def LI_(): return list(map(lambda x: int(x)-1, input().split()))
def II(): return int(input())
def IF(): return float(input())
def LS(): return list(map(list, input().split()))
def S(): return list(input().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')


def A():
    return


def B():
    return


def C():
    return


def D():
    return


def E():
    n, m, l = LI()
    dist = [[inf] * n for i in range(n)]

    for _ in range(m):
        a, b, c = LI_()
        c += 1
        if c > l:
            continue
        dist[a][b] = c
        dist[b][a] = c

    supply = [[n] * n for i in range(n)]
    for k in range(n):
        distk = dist[k]
        for i in range(n):
            if i == k:
                continue
            disti = dist[i]
            for j in range(i + 1, n):
                if disti[k] + distk[j] < disti[j]:
                    disti[j] = disti[k] + distk[j]
                    dist[j][i] = disti[j]

    lis = [[] for i in range(n)]
    for i in range(n):
        for j in range(i + 1, n):
            if dist[i][j] <= l:
                supply[i][j] = 0
                supply[j][i] = 0
                lis[i].append(j)
                lis[j].append(i)

    for i in range(n):
        q = []
        for k in lis[i]:
            heappush(q, (0, k))
        supplyi = supply[i]

        while q:
            time, p = heappop(q)
            for k in lis[p]:
                if supplyi[k] > time + 1:
                    supplyi[k] = time + 1
                    heappush(q, (time + 1, k))

    q = II()
    for _ in range(q):
        s, t = LI_()
        if dist[s][t] == inf:
            print(-1)
            continue
        else:
            print(supply[s][t])
    return



def F():
    return


def G():
    return


def H():
    return


if __name__ == '__main__':
    E()

Solution (Python):
import sys
from scipy.sparse.csgraph import floyd_warshall
import numpy as np
input = sys.stdin.readline

N, M, L = map(int, input().split())
graph = np.array([[0 if i == j else float("inf")
                   for i in range(N)] for j in range(N)])
for _ in range(M):
    a, b, c = map(int, input().split())
    graph[a - 1][b - 1] = c
    graph[b - 1][a - 1] = c

Q = int(input())
dist = floyd_warshall(graph)


graph2 = np.array([[float("inf")] * N for _ in range(N)])
np.fill_diagonal(graph2, 0)
graph2[(dist <= L) & (dist != 0)] = 1

dist2 = floyd_warshall(graph2)
dist2[dist2 == float("inf")] = 0

for _ in range(Q):
    s, t = map(int, input().split())
    print(int(dist2[s - 1, t - 1]) - 1)

Solution (Python):
import sys
from scipy.sparse.csgraph import floyd_warshall
import numpy as np
input = sys.stdin.readline

N, M, L = map(int, input().split())
graph = np.array([[0 if i == j else float("inf")
                   for i in range(N)] for j in range(N)])
for _ in range(M):
    a, b, c = map(int, input().split())
    graph[a - 1][b - 1] = c
    graph[b - 1][a - 1] = c

Q = int(input())
dist = floyd_warshall(graph)


graph2 = np.array([[float("inf")] * N for _ in range(N)])
np.fill_diagonal(graph2, 0)
graph2[(dist <= L) & (dist != 0)] = 1

dist2 = floyd_warshall(graph2)
dist2[dist2 == float("inf")] = 0

for _ in range(Q):
    s, t = map(int, input().split())
    print(int(dist2[s - 1, t - 1]) - 1)

Solution (Python):
import numpy as np
import sys
from scipy.sparse.csgraph import floyd_warshall,csgraph_from_dense
from scipy.sparse import csr_matrix
input = sys.stdin.readline
def inputs():return [int(x) for x in input().split()]
N,M,L = inputs()
ABC =[inputs() for _ in range(M)]
graph = [[10**13]*(N+1) for _ in range(N+1)]
for a,b,c in ABC:
    graph[a][b] = c
G = csgraph_from_dense(graph, null_value=10**13)
dist_mat = floyd_warshall(graph,directed=False)
graph2 = np.array([[10**13]*(N+1) for _ in range(N+1)])
np.fill_diagonal(graph2,0)
graph2[dist_mat<=L]=1
dist_mat2 = floyd_warshall(graph2,directed=False)
dist_mat2[dist_mat2==10**13]=0
Q = int(input())
for i in range(Q):
    s,t = inputs()
    print(int(dist_mat2[s,t])-1)

Solution (Python):
from enum import Enum
from queue import Queue

import numpy as np

import collections
import bisect
import sys
import math

from scipy.sparse.csgraph import floyd_warshall

BIG_NUM = 200000000000
MOD = 1000000007
EPS = 0.000000001

def warshall_floyd(d,n):
    
    for k in range(n):
        for i in range(n):
            for j in range(n):
                d[i][j] = min(d[i][j],d[i][k] + d[k][j])
    return d

N,M,L = map(int,input().split())
d = [[float("inf") for i in range(N)] for j in range(N)]
for i in range(M):
    a,b,c = map(int,input().split())
    d[a-1][b-1] = c
    d[b-1][a-1] = c
for i in range(N):
    d[i][i] = 0
d = floyd_warshall(d)
for i in range(N):
    for j in range(i,N):
        if d[i][j] <= L:
            d[i][j] = 1
            d[j][i] = 1
        else:
            d[i][j] = float("inf")
            d[j][i] = float("inf")
    d[i][i] = 1
d = floyd_warshall(d)
Q = int(input())
for q in range(Q):
    s,t = map(int,input().split())
    if d[s-1][t-1] == float("inf"):
        print(-1)
    else:
        print(int(d[s-1][t-1])-1)

Solution (Python):
n,m,l=map(int,input().split())
abcs=[list(map(int,input().split())) for _ in range(m)]
for i in range(m):
	abcs[i][0]-=1
	abcs[i][1]-=1
inf =1234567890123456
dist = [[inf for i in range(n)] for j in range(n)]
for i in range(n):
	dist[i][i] = 0

for i in range(m):
	a=abcs[i][0]
	b=abcs[i][1]
	c=abcs[i][2]
	dist[a][b] = dist[b][a] = c

for k in range(n):
	for i in range(n):
		for j in range(n):
			dist[i][j] = min(dist[i][j],dist[i][k]+dist[k][j])

ans = [[inf for i in range(n)] for j in range(n)]
for i in range(n):
	ans[i][i]=0
for i in range(n):
	for j in range(i+1,n):
		if dist[i][j]<=l:
			ans[i][j]=ans[j][i]=1
for k in range(n):
	for i in range(n):
		for j in range(n):
			ans[i][j] = min(ans[i][j],ans[i][k]+ans[k][j])


for _ in range(int(input())):
	f,t=map(int,input().split())
	f-=1
	t-=1
	print(ans[f][t]-1 if ans[f][t]!=inf else -1)

Solution (Python):
import numpy as np
from scipy.sparse import csr_matrix
from scipy.sparse.csgraph import dijkstra

n, m, l = map(int, input().split())
abc = []
for _ in range(m):
    abc.append(map(int, input().split()))
q = int(input())
st = []
for _ in range(q):
    st.append(map(int, input().split()))

adjacency_matrix = np.zeros((n, n))
for a, b, c in abc:
    adjacency_matrix[a-1, b-1] = c
    adjacency_matrix[b-1, a-1] = c

shotest = dijkstra(adjacency_matrix)
fuel_once = np.where(shotest <= l, 1, 0)
fuel_times = dijkstra(fuel_once-np.eye(n))

for s, t in st:
    ans = fuel_times[s-1][t-1]
    if np.isinf(ans):
        print(-1)
    else:
        print(int(ans) - 1)

Solution (Python):
from scipy.sparse.csgraph import floyd_warshall

N, M, L = map(int, input().split())

G = [list(map(int, input().split())) for _ in range(M)]
Q = int(input())
Query = [list(map(int, input().split())) for _ in range(Q)]


nei_graph = [[0] * N for _ in range(N)]
for a, b, c in G:
    nei_graph[a - 1][b - 1] = c
    nei_graph[b - 1][a - 1] = c


nei_graph = floyd_warshall(nei_graph)


for i in range(N):
    for j in range(N):
        if nei_graph[i][j] <= L:
            nei_graph[i][j] = 1
        else:
            nei_graph[i][j] = 0

nei_graph = floyd_warshall(nei_graph)

for start, end in Query:
    if nei_graph[start - 1][end - 1] - 1 == float('inf'):
        print(-1)
    else:
        print(int(nei_graph[start - 1][end - 1] - 1))

Solution (Python):
N, M, L = map(int,input().split())
MAX=99999999999
A=[]
B=[]
C=[]
D=[[MAX for _ in range(N)] for _ in range(N)]
F=[[MAX for _ in range(N)] for _ in range(N)]
s=[]
t=[]
 
for i in range(M):
    l=list(map(int,input().split()))
    A.append(l[0]-1)
    B.append(l[1]-1)
    C.append(l[2])
 
 
 
Q=int(input())
 
for i in range(Q):
    m=list(map(int,input().split()))
    s.append(m[0]-1)
    t.append(m[1]-1)
 
 
for i in range(M):
    if C[i]>L : continue
    D[A[i]][B[i]]=C[i]
    D[B[i]][A[i]]=C[i]
 
for i in range(N):  D[i][i]=0
 
for k in range(N):
    for i in range(N):
        for j in range(N):
            if (D[i][k]+D[k][j])<D[i][j] :
                D[i][j]=D[i][k]+D[k][j]
 
for i in range(N):
    for j in range(N):
        if i==j : continue
        if D[i][j]<=L: F[i][j]=1
 
 
for i in range(N):  F[i][i]=0
 
for k in range(N):
    for i in range(N):
        for j in range(N):
            if (F[i][k]+F[k][j])<F[i][j] :
                F[i][j]=F[i][k]+F[k][j]
 
 
for p in range(Q) :
    if F[s[p]][t[p]] < MAX :
        print(F[s[p]][t[p]]-1)
    else :
        print(-1)

Solution (Python):
import sys
sys.setrecursionlimit(1000000000)
ii = lambda: int(input())
ii0 = lambda: ii() - 1
mis = lambda: map(int, input().split())
lmis = lambda: list(mis())
INF = float('inf')

def main():
    N,M,L = mis()
    from scipy.sparse.csgraph import floyd_warshall
    import numpy as np
    INF = np.iinfo(np.int64).max
    d = np.full((N,N), INF, dtype=np.uint64)
    for i in range(N):
        d[i,i] = 0
    
    for _ in range(M):
        a,b,c = mis()
        a -= 1
        b -= 1
        if c <= L:
            d[a,b] = c
            d[b,a] = c
    
    '''
    for k in range(N):
        for i in range(N):
            np.minimum(d[i,:], d[i,k]+d[k,:], out=d[i,:])    
    '''
    d = floyd_warshall(d)
    
    d2 = np.full((N,N), INF, dtype=np.uint64)
    for i in range(N):
        d2[i, i] = 0
    for i in range(N):
        for j in range(N):
            if d[i, j] <= L:
                d2[i, j] = 1
    
    '''
    for k in range(N):
        for i in range(N):
            np.minimum(d2[i,:], d2[i,k]+d2[k,:], out=d2[i,:])    
    '''
    d2 = floyd_warshall(d2)
    
    Q = ii()
    for _ in range(Q):
        s,t = mis()
        s -= 1
        t -= 1
        dist = d2[s,t]
        if dist == INF:
            print(-1)
        else:
            print(int(dist)-1)




main()

Solution (Python):
from scipy.sparse.csgraph import floyd_warshall

N, M, L = map(int, input().split())
edges = [[0] * N for _ in range(N)]
for _ in range(M):
    a, b, c = map(int, input().split())
    edges[a - 1][b - 1] = c
    edges[b - 1][a - 1] = c

Q = int(input())
st = []
for _ in range(Q):
    st.append([int(j) - 1 for j in input().split()])

edges = floyd_warshall(edges)

for i in range(N):
    for j in range(N):
        if edges[i][j] <= L:
            edges[i][j] = 1
        else:
            edges[i][j] = 0

edges = floyd_warshall(edges)

for i, j in st:
    if edges[i][j] == float("inf"):
        print(-1)
    else:
        print(int(edges[i][j]) - 1)