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



Sample input:
3 2 5
1 2 3
2 3 3
2
3 2
1 3


Sample output:
0
1

Submission status: Time Limit Exceeded

Solution code:
from collections import defaultdict
from heapq import heappop, heappush


class Graph(object):
  
    def __init__(self):
        self.graph = defaultdict(list)

    def __len__(self):
        return len(self.graph)

    def add_edge(self, src, dst, weight=1):
        self.graph[src].append((dst, weight))

    def get_nodes(self):
        return self.graph.keys()


class Dijkstra(object):

    def __init__(self, graph, start,l):
        self.g = graph.graph

        # startノードからの最短距離
        # startノードは0, それ以外は無限大で初期化
        self.dist = defaultdict(lambda: float('inf'))
        self.dist[start] = 0

        # 最短経路での1つ前のノード
        self.prev = defaultdict(lambda: None)

        # startノードをキューに入れる
        self.Q = []
        heappush(self.Q, (self.dist[start], start))

        while self.Q:
            # 優先度（距離）が最小であるキューを取り出す
            dist_u, u = heappop(self.Q)
            if self.dist[u] < dist_u:
                continue
            for v, weight in self.g[u]:
                alt = dist_u + weight
                if dist_u != 0:
                  if (dist_u - 1) // l != (alt - 1) // l:
                    alt = ((dist_u - 1) // l + 1) * l + weight
                if self.dist[v] > alt:
                    self.dist[v] = alt
                    self.prev[v] = u
                    heappush(self.Q, (alt, v))

    def shortest_distance(self, goal):
        if self.dist[goal] == float("inf"):
          return -1
        return (self.dist[goal] - 1) // l


    def shortest_path(self, goal):
        path = []
        node = goal
        while node is not None:
            path.append(node)
            node = self.prev[node]
        return path[::-1]

n,m,l = map(int, input().split())
abc = [list(map(int, input().split())) for i in range(m)]
q = int(input())
st = [list(map(int, input().split())) for i in range(q)]
path = Graph()
for i in abc:
  a,b,c = i[0], i[1], i[2]
  if c <= l:
    path.add_edge(a-1, b-1, c)
    path.add_edge(b-1, a-1, c)
for i in st:
  s,t = i[0]-1, i[1]-1
  s_path = Dijkstra(path, s, l)
  ans = s_path.shortest_distance(t)
  print(ans)

Submission status: Time Limit Exceeded

Solution code:
# -*- coding: utf-8 -*-
import random
import sys

sys.setrecursionlimit(100000)
input = sys.stdin.readline

INF = 2**63-1

def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))


def warshall_floyd(g):
    N = len(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])
    return g


def slv(N, M, L, ABC, Q, ST):
    g = [[INF]*(N) for _ in range(N)]

    for a, b, c in ABC:
        if c > L:
            continue
        g[a-1][b-1] = c
        g[b-1][a-1] = c

    d = warshall_floyd(g)

    gg = [[INF]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if d[u][v] <= L:
                gg[u][v] = 1

    d = warshall_floyd(gg)

    for s, t in ST:
        c = d[s-1][t-1]
        if c != INF:
            print(c-1)
        else:
            print(-1)


def main():
    N, M, L = read_int_n()
    ABC = [read_int_n() for _ in range(M)]
    Q = read_int()
    ST = [read_int_n() for _ in range(Q)]

    (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
def slv():
    import sys
    input = sys.stdin.readline
    N, M, L = list(map(int, input().rstrip('\n').split()))
    g = [[sys.maxsize]*(N) for _ in range(N)]
    gg = [[sys.maxsize]*(N) for _ in range(N)]

    for i in range(N):
        g[i][i] = 0
    for _ in range(M):
        a, b, c = list(map(int, input().rstrip('\n').split()))
        if c <= L:
            g[a-1][b-1] = c
            g[b-1][a-1] = c
    
    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])
    
    for u in range(N):
        for v in range(N):
            if g[u][v] <= L:
                gg[u][v] = 1
    
    for k in range(N):
        for i in range(N):
            for j in range(N):
                gg[i][j] = min(gg[i][j], gg[i][k] + gg[k][j])

    Q = int(input())
    for _ in range(Q):
        s, t = list(map(int, input().rstrip('\n').split()))
        c = gg[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    slv()

if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import sys

input = sys.stdin.readline

def slv():
    N, M, L = list(map(int, input().rstrip('\n').split()))
    g = [[sys.maxsize]*(N) for _ in range(N)]
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    
    for i in range(N):
        g[i][i] = 0
    for _ in range(M):
        a, b, c = list(map(int, input().rstrip('\n').split()))
        if c <= L:
            g[a-1][b-1] = c
            g[b-1][a-1] = c
    
    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])
    
    for u in range(N):
        for v in range(N):
            if g[u][v] <= L:
                gg[u][v] = 1
    
    for k in range(N):
        for i in range(N):
            for j in range(N):
                gg[i][j] = min(gg[i][j], gg[i][k] + gg[k][j])

    Q = int(input())
    for _ in range(Q):
        s, t = list(map(int, input().rstrip('\n').split()))
        c = gg[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    slv()
    # N, M, L = read_int_n()
    # ABC = [read_int_n() for _ in range(M)]
    # Q = read_int()
    # ST = [read_int_n() for _ in range(Q)]
    
    # (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import sys

input = sys.stdin.readline

def slv():
    N, M, L = list(map(int, input().rstrip('\n').split()))
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for i in range(N):
        g[i][i] = 0
    for _ in range(M):
        a, b, c = list(map(int, input().rstrip('\n').split()))
        if c <= L:
            g[a-1][b-1] = c
            g[b-1][a-1] = c
    
    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])
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if g[u][v] <= L:
                gg[u][v] = 1
    
    for k in range(N):
        for i in range(N):
            for j in range(N):
                gg[i][j] = min(gg[i][j], gg[i][k] + gg[k][j])

    Q = int(input())
    for _ in range(Q):
        s, t = list(map(int, input().rstrip('\n').split()))
        c = gg[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    slv()
    # N, M, L = read_int_n()
    # ABC = [read_int_n() for _ in range(M)]
    # Q = read_int()
    # ST = [read_int_n() for _ in range(Q)]
    
    # (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import sys

input = sys.stdin.readline

def slv():
    N, M, L = list(map(int, input().split()))
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for i in range(N):
        g[i][i] = 0
    for _ in range(M):
        a, b, c = list(map(int, input().split()))
        if c <= L:
            g[a-1][b-1] = c
            g[b-1][a-1] = c
    
    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])
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if g[u][v] <= L:
                gg[u][v] = 1
    
    for k in range(N):
        for i in range(N):
            for j in range(N):
                gg[i][j] = min(gg[i][j], gg[i][k] + gg[k][j])

    Q = int(input())
    for _ in range(Q):
        s, t = list(map(int, input().split()))
        c = gg[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    slv()
    # N, M, L = read_int_n()
    # ABC = [read_int_n() for _ in range(M)]
    # Q = read_int()
    # ST = [read_int_n() for _ in range(Q)]
    
    # (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import sys

input = sys.stdin.readline


def read_int():
    return int(input())

def slv():
    N, M, L = list(map(int, input().split()))
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for i in range(N):
        g[i][i] = 0
    for _ in range(M):
        a, b, c = list(map(int, input().split()))
        if c <= L:
            g[a-1][b-1] = c
            g[b-1][a-1] = c
    
    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])
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if g[u][v] <= L:
                gg[u][v] = 1
    
    for k in range(N):
        for i in range(N):
            for j in range(N):
                gg[i][j] = min(gg[i][j], gg[i][k] + gg[k][j])

    Q = read_int()
    for _ in range(Q):
        s, t = list(map(int, input().split()))
        c = gg[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    slv()
    # N, M, L = read_int_n()
    # ABC = [read_int_n() for _ in range(M)]
    # Q = read_int()
    # ST = [read_int_n() for _ in range(Q)]
    
    # (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import random
import sys

input = sys.stdin.readline


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))


def slv():
    N, M, L = list(map(int, input().split()))
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for i in range(N):
        g[i][i] = 0
    for _ in range(M):
        a, b, c = list(map(int, input().split()))
        if c <= L:
            g[a-1][b-1] = c
            g[b-1][a-1] = c
    
    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])
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if g[u][v] <= L:
                gg[u][v] = 1
    
    for k in range(N):
        for i in range(N):
            for j in range(N):
                gg[i][j] = min(gg[i][j], gg[i][k] + gg[k][j])

    Q = read_int()
    for _ in range(Q):
        s, t = list(map(int, input().split()))
        c = gg[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    slv()
    # N, M, L = read_int_n()
    # ABC = [read_int_n() for _ in range(M)]
    # Q = read_int()
    # ST = [read_int_n() for _ in range(Q)]
    
    # (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import random
import sys

sys.setrecursionlimit(100000)
input = sys.stdin.readline


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))

def warshall_floyd(g):
    d = g
    N = len(g)
    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


def slv():
    N, M, L = list(map(int, input().split()))
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for i in range(N):
        g[i][i] = 0
    for _ in range(M):
        a, b, c = list(map(int, input().split()))
        if c <= L:
            g[a-1][b-1] = c
            g[b-1][a-1] = c
    
    d = g
    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])
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if d[u][v] <= L:
                gg[u][v] = 1
    
    d = gg
    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])

    Q = read_int()
    for _ in range(Q):
        s, t = list(map(int, input().split()))
        c = d[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    slv()
    # N, M, L = read_int_n()
    # ABC = [read_int_n() for _ in range(M)]
    # Q = read_int()
    # ST = [read_int_n() for _ in range(Q)]
    
    # (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import random
import sys

sys.setrecursionlimit(100000)
input = sys.stdin.readline


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))

def warshall_floyd(g):
    d = g
    N = len(g)
    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


def slv():
    N, M, L = list(map(int, input().split()))
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for i in range(N):
        g[i][i] = 0
    for _ in range(M):
        a, b, c = list(map(int, input().split()))
        if c > L:
            continue
        g[a-1][b-1] = c
        g[b-1][a-1] = c
    
    d = g
    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])
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if d[u][v] <= L:
                gg[u][v] = 1
    
    d = gg
    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])

    Q = read_int()
    for _ in range(Q):
        s, t = list(map(int, input().split()))
        c = d[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    slv()
    # N, M, L = read_int_n()
    # ABC = [read_int_n() for _ in range(M)]
    # Q = read_int()
    # ST = [read_int_n() for _ in range(Q)]
    
    # (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import random
import sys

sys.setrecursionlimit(100000)
input = sys.stdin.readline


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))

def warshall_floyd(g):
    d = g
    N = len(g)
    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


def slv():
    N, M, L = read_int_n()
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for i in range(N):
        g[i][i] = 0
    for _ in range(M):
        a, b, c = read_int_n()
        if c > L:
            continue
        g[a-1][b-1] = c
        g[b-1][a-1] = c
    
    d = g
    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])
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if d[u][v] <= L:
                gg[u][v] = 1
    
    d = gg
    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])

    Q = read_int()
    for _ in range(Q):
        s, t = read_int_n()
        c = d[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    slv()
    # N, M, L = read_int_n()
    # ABC = [read_int_n() for _ in range(M)]
    # Q = read_int()
    # ST = [read_int_n() for _ in range(Q)]
    
    # (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import random
import sys

sys.setrecursionlimit(100000)
input = sys.stdin.readline


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))

def warshall_floyd(g):
    d = g
    N = len(g)
    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


def slv(N, M, L, ABC, Q, ST):
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for i in range(N):
        g[i][i] = 0
    for a, b, c in ABC:
        if c > L:
            continue
        g[a-1][b-1] = c
        g[b-1][a-1] = c
    
    d = g
    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])
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if d[u][v] <= L:
                gg[u][v] = 1
    
    d = gg
    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 s, t in ST:
        c = d[s-1][t-1]
        if c != sys.maxsize:
            print(c-1)
        else:
            print(-1)



def main():
    N, M, L = read_int_n()
    ABC = [read_int_n() for _ in range(M)]
    Q = read_int()
    ST = [read_int_n() for _ in range(Q)]
    
    (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import random
import sys

sys.setrecursionlimit(100000)
input = sys.stdin.readline


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))

def warshall_floyd(g):
    d = g
    N = len(g)
    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


def slv(N, M, L, ABC, Q, ST):
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for i in range(N):
        g[i][i] = 0
    for a, b, c in ABC:
        if c > L:
            continue
        g[a-1][b-1] = c
        g[b-1][a-1] = c
    
    d = warshall_floyd(g)
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if d[u][v] <= L:
                gg[u][v] = 1
    dd = warshall_floyd(gg)

    for s, t in ST:
        d = dd[s-1][t-1]
        if d != sys.maxsize:
            print(d-1)
        else:
            print(-1)



def main():
    N, M, L = read_int_n()
    ABC = [read_int_n() for _ in range(M)]
    Q = read_int()
    ST = [read_int_n() for _ in range(Q)]
    
    (slv(N, M, L, ABC, Q, ST))

    # N = 300
    # M = (N*(N-1))//2
    # L = random.randint(1, 10**9)
    # ABC = []
    # for i in range(1, N+1):
    #     for j in range(i+1, N+1):
    #         ABC.append([i, j, random.randint(1, 10**9)])
    
    # ST = []
    # for i in range(1, N+1):
    #     for j in range(1, N+1):
    #         if i == j:
    #             continue
    #         ST.append([i, j])
    # Q = len(ST)
    # # (slv(N, M, L, ABC, Q, ST))

    # print(N, M, L)
    # for a, b, c in ABC:
    #     print(a, b, c)
    # print(Q)
    # for s, t in ST:
    #     print(s, t)


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:
def WarshallFloyd(M):
    N = len(M)
    for k in range(N):
        for j in range(N):
            for i in range(N):
                M[i][j] = min(M[i][j], M[i][k] + M[k][j])
    return M

INF = float("inf")

N, M, L, *I = map(int, open(0).read().split())
ABC, ST = I[:3 * M], I[3 * M + 1:]

E = [[INF] * N for _ in range(N)]
for a, b, c in zip(*[iter(ABC)] * 3):
    E[a - 1][b - 1] = E[b - 1][a - 1] = c


E = WarshallFloyd(E)

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

E = WarshallFloyd(E)

for s, t in zip(*[iter(ST)] * 2):
    a = E[s - 1][t - 1] - 1
    print(-1 if a == INF else a)

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import random
import sys

sys.setrecursionlimit(100000)
input = sys.stdin.readline


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))

def warshall_floyd(g):
    d = g
    N = len(g)
    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


def slv(N, M, L, ABC, Q, ST):
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for a, b, c in ABC:
        if c > L:
            continue
        g[a-1][b-1] = c
        g[b-1][a-1] = c
    
    d = warshall_floyd(g)
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if d[u][v] <= L:
                gg[u][v] = 1
    dd = warshall_floyd(gg)

    for s, t in ST:
        d = dd[s-1][t-1]
        if d != sys.maxsize:
            print(d-1)
        else:
            print(-1)



def main():
    N, M, L = read_int_n()
    ABC = [read_int_n() for _ in range(M)]
    Q = read_int()
    ST = [read_int_n() for _ in range(Q)]
    
    (slv(N, M, L, ABC, Q, ST))

    # N = 300
    # M = (N*(N-1))//2
    # L = random.randint(1, 10**9)
    # ABC = []
    # for i in range(1, N+1):
    #     for j in range(i+1, N+1):
    #         ABC.append([i, j, random.randint(1, 10**9)])
    
    # ST = []
    # for i in range(1, N+1):
    #     for j in range(1, N+1):
    #         if i == j:
    #             continue
    #         ST.append([i, j])
    # Q = len(ST)
    # # (slv(N, M, L, ABC, Q, ST))

    # print(N, M, L)
    # for a, b, c in ABC:
    #     print(a, b, c)
    # print(Q)
    # for s, t in ST:
    #     print(s, t)


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import sys

sys.setrecursionlimit(100000)
input = sys.stdin.readline


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))

def warshall_floyd(g):
    d = g
    N = len(g)
    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


def slv(N, M, L, ABC, Q, ST):
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for a, b, c in ABC:
        g[a-1][b-1] = c
        g[b-1][a-1] = c
    
    d = warshall_floyd(g)
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if d[u][v] <= L:
                gg[u][v] = 1
    dd = warshall_floyd(gg)

    for s, t in ST:
        d = dd[s-1][t-1]
        if d != sys.maxsize:
            print(d-1)
        else:
            print(-1)



def main():
    N, M, L = read_int_n()
    ABC = [read_int_n() for _ in range(M)]
    Q = read_int()
    ST = [read_int_n() for _ in range(Q)]
    (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:

# -*- coding: utf-8 -*-
import bisect
import heapq
import math
import random
import sys
from collections import Counter, defaultdict, deque
from decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal
from functools import lru_cache, reduce
from itertools import combinations, combinations_with_replacement, product, permutations
from operator import add, mul, sub

sys.setrecursionlimit(100000)
input = sys.stdin.readline


def read_int():
    return int(input())


def read_int_n():
    return list(map(int, input().split()))


def read_float():
    return float(input())


def read_float_n():
    return list(map(float, input().split()))


def read_str():
    return input().strip()


def read_str_n():
    return list(map(str, input().split()))


def error_print(*args):
    print(*args, file=sys.stderr)


def mt(f):
    import time

    def wrap(*args, **kwargs):
        s = time.time()
        ret = f(*args, **kwargs)
        e = time.time()

        error_print(e - s, 'sec')
        return ret

    return wrap


def warshall_floyd(g):
    d = g
    N = len(g)
    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

@mt
def slv(N, M, L, ABC, Q, ST):
    g = [[sys.maxsize]*(N) for _ in range(N)]
    for a, b, c in ABC:
        g[a-1][b-1] = c
        g[b-1][a-1] = c
    
    d = warshall_floyd(g)
    gg = [[sys.maxsize]*(N) for _ in range(N)]
    for u in range(N):
        for v in range(N):
            if d[u][v] <= L:
                gg[u][v] = 1
    dd = warshall_floyd(gg)

    for s, t in ST:
        d = dd[s-1][t-1]
        if d != sys.maxsize:
            print(d-1)
        else:
            print(-1)



def main():
    N, M, L = read_int_n()
    ABC = [read_int_n() for _ in range(M)]
    Q = read_int()
    ST = [read_int_n() for _ in range(Q)]
    (slv(N, M, L, ABC, Q, ST))

    # N = 300
    # M = (N*(N-1))//2
    # L = random.randint(1, 10**9)
    # ABC = []
    # for i in range(1, N+1):
    #     for j in range(i+1, N+1):
    #         ABC.append([i, j, random.randint(1, 10**9)])
    
    # ST = []
    # for i in range(1, N+1):
    #     for j in range(1, N+1):
    #         if i == j:
    #             continue
    #         ST.append([i, j])
    # Q = len(ST)
    # (slv(N, M, L, ABC, Q, ST))


if __name__ == '__main__':
    main()

Submission status: Time Limit Exceeded

Solution code:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		fuel = [[10000000,L+1] for i in range(N)]
		fuel[start][0] = 0
		fuel[start][1] = L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuel[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuel[j][0]:
						fuel[j][0], fuel[j][1] = nc, nm
						nq_append(j)
					elif nc==fuel[j][0] and nm>fuel[j][1]:
						fuel[j][1] = nm
						nq_append(j)

			queue = nq					# update target node

		ans = fuel[end][0]
		if ans==10000000: ans = -1

		fuellist[start] = fuel

		print(ans)


	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end][0]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start][0]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()