Buggy python submission (verdict: Time Limit Exceeded):
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    pre = []
    que = deque()
    for e in range(n):
        dis = [-1 for _ in range(n)]
        dis[e]=0
        if e == k-1:
            pre.append(0)
        else:
            que.append(e)
        while que:
            i = que.pop()
            for j in range(len(graph[i])):
                go = graph[i][j][0]
                d = graph[i][j][1]
                if dis[go]!=-1:
                    continue
                dis[go] = dis[i] + d
                if k-1 == go:
                    pre.append(dis[go])
                    que=deque()
                    break
                que.append(go)
    pre = tuple(pre)
    for _ in range(q):
        x,y = map(int,input().split())
        print( pre[x-1] + pre[y-1] ) 

if __name__ == "__main__":
    main()

Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    pre1 = []
    pre2 = []
    que = deque()
    for e in range(n):
        dis = [-1 for _ in range(n)]
        dis[e]=0
        if e == k-1:
            pre1.append(0)
        else:
            que.append(e)
        while que:
            tank = deque()
            while que:
                i = que.pop()
                for j in range(len(graph[i])):
                    go = graph[i][j][0]
                    d = graph[i][j][1]
                    if dis[go]!=-1:
                        continue
                    dis[go] = dis[i] + d
                    if k-1 == go:
                        pre1.append(dis[go])
                        tank=deque()
                        que=deque()
                        break
                    tank.append(go)
            que = tank
    que = deque()
    que.append(k-1)
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        tank = []
        while que:
            i = que.pop()
            for j in range(len(graph[i])):
                go = graph[i][j][0]
                d = graph[i][j][1]
                if dis[go]!=-1:
                    continue
                dis[go] = dis[i] + d
                tank.append(go)
        que = tank
    pre2 = dis

    pre1 = tuple(pre1)
    pre2 = tuple(pre2)
    for _ in range(q):
        x,y = map(int,input().split())
        print( pre1[x-1] + pre2[y-1] ) 

if __name__ == "__main__":
    main()

Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    pre1 = []
    pre2 = []
    que = deque()
    for e in range(n):
        que.append(e)
        dis = [0 for _ in range(n)]
        did = [False for _ in range(n)]
        did[e] = True
        if e == k-1:
            pre1.append(0)
        while que:
            tank = deque()
            while que:
                i = que.pop()
                for j in range(len(graph[i])):
                    go = graph[i][j][0]
                    d = graph[i][j][1]
                    if did[go]:
                        continue
                    dis[go] = dis[i] + d
                    if k-1 == go:
                        pre1.append(dis[go])
                        tank=deque()
                        que=deque()
                        break
                    tank.append(go)
                    did[go] = True
            que = tank
    que = deque()
    que.append(k-1)
    dis = [0 for _ in range(n)]
    did = [False for _ in range(n)]
    did[k-1] = True
    while que:
        tank = []
        while que:
            i = que.pop()
            for j in range(len(graph[i])):
                go = graph[i][j][0]
                d = graph[i][j][1]
                if did[go]:
                    continue
                dis[go] = dis[i] + d
                tank.append(go)
                did[go] = True
        que = tank
    pre2 = dis

    pre1 = tuple(pre1)
    pre2 = tuple(pre2)
    for _ in range(q):
        x,y = map(int,input().split())
        print( pre1[x-1] + pre2[y-1] ) 

if __name__ == "__main__":
    main()

Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    pre1 = []
    pre2 = []
    for e in range(n):
        que = [e]
        dis = [0 for _ in range(n)]
        did = [False for _ in range(n)]
        did[e] = True
        if e == k-1:
            pre1.append(0)
        while que:
            tank = []
            for i in que:
                for j in range(len(graph[i])):
                    go = graph[i][j][0]
                    d = graph[i][j][1]
                    if did[go]:
                        continue
                    dis[go] = dis[i] + d
                    if k-1 == go:
                        pre1.append(dis[go])
                        tank=[]
                        que=[]
                        break
                    tank.append(go)
                    did[go] = True
            que = tank
        
    que = [k-1]
    dis = [0 for _ in range(n)]
    did = [False for _ in range(n)]
    did[k-1] = True
    while que:
        tank = []
        for i in que:
            for j in range(len(graph[i])):
                go = graph[i][j][0]
                d = graph[i][j][1]
                if did[go]:
                    continue
                dis[go] = dis[i] + d
                tank.append(go)
                did[go] = True
        que = tank
    pre2 = dis
 
    pre1 = tuple(pre1)
    pre2 = tuple(pre2)
    for _ in range(q):
        x,y = map(int,input().split())
        print( pre1[x-1] + pre2[y-1] ) 

if __name__ == "__main__":
    main()

Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
# input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7
    
def inp(): # n=1
    return int(input())
def inpm(): # x=1,y=2
    return map(int,input().split())
def inpl(): # a=[1,2,3,4,5,...,n]
    return list(map(int, input().split()))
def inpls(): # a=['1','2','3',...,'n']
    return list(input().split())
def inplm(n): # x=[] 複数行
    return list(int(input()) for _ in range(n))
def inpll(n): # [[1,1,1,1],[2,2,2,2],[3,3,3,3]]
    return sorted([list(map(int, input().split())) for _ in range(n)])
def graphm():
    n=inp()
    g=[[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=inpm()
        a-=1
        b-=1
        g[a].append((b,w))
        g[b].append((a,w))
    return n,g

def dfs(start,goal,n,g):
    que = [start-1]
    dis = [0 for _ in range(n)]
    did = [False for _ in range(n)]
    did[start-1] = True
    if start == goal:
        return 0
    while que:
        tank = []
        for i in que:
            for j in range(len(g[i])):
                go = g[i][j][0]
                d = g[i][j][1]
                if did[go]:
                    continue
                dis[go] = dis[i] + d
                if goal-1 == go:
                    return dis[go]
                tank.append(go)
                did[go] = True
        que = tank
 
def main():
    n,graph = graphm()
    q,k = inpm()
    pre1 = []
    pre2 = []
    for i in range(n):
        pre1.append(dfs(i+1,k,n,graph))
        pre2.append(dfs(k,i+1,n,graph))
    for _ in range(q):
        x,y = inpm()
        print( pre1[x-1] + pre2[y-1] ) 

if __name__ == "__main__":
    main()

Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
# input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7
    
def inp(): # n=1
    return int(input())
def inpm(): # x=1,y=2
    return map(int,input().split())
def inpl(): # a=[1,2,3,4,5,...,n]
    return list(map(int, input().split()))
def inpls(): # a=['1','2','3',...,'n']
    return list(input().split())
def inplm(n): # x=[] 複数行
    return list(int(input()) for _ in range(n))
def inpll(n): # [[1,1,1,1],[2,2,2,2],[3,3,3,3]]
    return sorted([list(map(int, input().split())) for _ in range(n)])
def graphm():
    n=inp()
    g=[[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=inpm()
        a-=1
        b-=1
        g[a].append((b,w))
        g[b].append((a,w))
    return n,g
def dijkstra(s,to,n,g): # sからの最短距離 頂点数n
    s -= 1
    que = []
    d = [10**15 for _ in range(n)]
    d[s] = 0
    heappush( que,(0,s) )
    while len(que)>0:
        p =  heappop(que)
        v = p[1]
        if d[v] < p[0]:
            if p[1]==to-1:
                break
            continue
        for i in range(len(g[v])):
            edge = g[v][i]
            if d[edge[0]] > d[v] + edge[1]:
                d[edge[0]] = d[v] + edge[1]
                heappush( que,(d[edge[0]] , edge[0]) )
    return d[to-1]
 
def dijkstra1(s,n,g): # sからの最短距離 頂点数n
    s -= 1
    que = []
    d = [10**15 for _ in range(n)]
    d[s] = 0
    heappush( que,(0,s) )
    while len(que)>0:
        p =  heappop(que)
        v = p[1]
        if d[v] < p[0]:
            continue
        for i in range(len(g[v])):
            edge = g[v][i]
            if d[edge[0]] > d[v] + edge[1]:
                d[edge[0]] = d[v] + edge[1]
                heappush( que,(d[edge[0]] , edge[0]) )
    return d
 
def main():
    n,graph = graphm()
    q,k = inpm()
    pre2 = dijkstra1(k,n,graph)
    pre1=[]
    for i in range(n):
        pre1.append(dijkstra(i+1,k,n,graph))
    for _ in range(q):
        x,y = inpm()
        print( pre1[x-1] + pre2[y-1] ) 

if __name__ == "__main__":
    main()

Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from heapq import heappop, heappush
input = sys.stdin.readline

def inp(): # n=1
    return int(input())
def inpm(): # x=1,y=2
    return map(int,input().split())
def inpl(): # a=[1,2,3,4,5,...,n]
    return list(map(int, input().split()))
def inpls(): # a=['1','2','3',...,'n']
    return list(input().split())
def inplm(n): # x=[] 複数行
    return list(int(input()) for _ in range(n))
def inpll(n): # [[1,1,1,1],[2,2,2,2],[3,3,3,3]]
    return sorted([list(map(int, input().split())) for _ in range(n)])
def graphm():
    n=inp()
    g=[[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=inpm()
        a-=1
        b-=1
        g[a].append((b,w))
        g[b].append((a,w))
    return n,g
def dijkstra(s,to,n,g): # sからの最短距離 頂点数n
    s -= 1
    que = []
    d = [10**15 for _ in range(n)]
    d[s] = 0
    heappush( que,(0,s) )
    while len(que)>0:
        p =  heappop(que)
        v = p[1]
        if d[v] < p[0]:
            if p[1]==to-1:
                break
            continue
        for i in range(len(g[v])):
            edge = g[v][i]
            if d[edge[0]] > d[v] + edge[1]:
                d[edge[0]] = d[v] + edge[1]
                heappush( que,(d[edge[0]] , edge[0]) )
    return d[to-1]

def dijkstra1(s,n,g): # sからの最短距離 頂点数n
    s -= 1
    que = []
    d = [10**15 for _ in range(n)]
    d[s] = 0
    heappush( que,(0,s) )
    while len(que)>0:
        p =  heappop(que)
        v = p[1]
        if d[v] < p[0]:
            continue
        for i in range(len(g[v])):
            edge = g[v][i]
            if d[edge[0]] > d[v] + edge[1]:
                d[edge[0]] = d[v] + edge[1]
                heappush( que,(d[edge[0]] , edge[0]) )
    return d

def main():
    n,graph = graphm()
    q,k = inpm()
    pre = dijkstra1(k,n,graph)
    for _ in range(q):
        x,y = inpm()
        print( dijkstra(x,k,n,graph) + pre[y-1] )    

if __name__ == "__main__":
    main()


Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from heapq import heappop, heappush
input = sys.stdin.readline

def inp(): # n=1
    return int(input())
def inpm(): # x=1,y=2
    return map(int,input().split())
def inpl(): # a=[1,2,3,4,5,...,n]
    return list(map(int, input().split()))
def inpls(): # a=['1','2','3',...,'n']
    return list(input().split())
def inplm(n): # x=[] 複数行
    return list(int(input()) for _ in range(n))
def inpll(n): # [[1,1,1,1],[2,2,2,2],[3,3,3,3]]
    return sorted([list(map(int, input().split())) for _ in range(n)])
def graphm():
    n=inp()
    g=[[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=inpm()
        a-=1
        b-=1
        g[a].append((b,w))
        g[b].append((a,w))
    return n,g
def dijkstra(s,to,n,g): # sからの最短距離 頂点数n
    s -= 1
    que = []
    d = [10**15 for _ in range(n)]
    d[s] = 0
    heappush( que,(0,s) )
    while len(que)>0:
        p =  heappop(que)
        v = p[1]
        if d[v] < p[0]:
            continue
        for i in range(len(g[v])):
            edge = g[v][i]
            if d[edge[0]] > d[v] + edge[1]:
                d[edge[0]] = d[v] + edge[1]
                heappush( que,(d[edge[0]] , edge[0]) )
    return d[to-1]

def dijkstra1(s,n,g): # sからの最短距離 頂点数n
    s -= 1
    que = []
    d = [10**15 for _ in range(n)]
    d[s] = 0
    heappush( que,(0,s) )
    while len(que)>0:
        p =  heappop(que)
        v = p[1]
        if d[v] < p[0]:
            continue
        for i in range(len(g[v])):
            edge = g[v][i]
            if d[edge[0]] > d[v] + edge[1]:
                d[edge[0]] = d[v] + edge[1]
                heappush( que,(d[edge[0]] , edge[0]) )
    return d

def main():
    n,graph = graphm()
    q,k = inpm()
    pre = dijkstra1(k,n,graph)
    for _ in range(q):
        x,y = inpm()
        print( dijkstra(x,k,n,graph) + pre[y-1] )    

if __name__ == "__main__":
    main()


Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import Counter,defaultdict,deque
import sys
import bisect
import math
import itertools
import string
import queue
import copy
import random
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def inp(): # n=1
    return int(input())
def inpm(): # x=1,y=2
    return map(int,input().split())
def inpl(): # a=[1,2,3,4,5,...,n]
    return list(map(int, input().split()))
def inpls(): # a=['1','2','3',...,'n']
    return list(input().split())
def inplm(n): # x=[] 複数行
    return list(int(input()) for _ in range(n))
def inpll(n): # [[1,1,1,1],[2,2,2,2],[3,3,3,3]]
    return sorted([list(map(int, input().split())) for _ in range(n)])
def graphm():
    n=inp()
    g=[[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=inpm()
        a-=1
        b-=1
        g[a].append((b,w))
        g[b].append((a,w))
    return n,g
def dijkstra(s,to,n,g): # sからの最短距離 頂点数n
    s -= 1
    que = []
    d = [10**15 for _ in range(n)]
    d[s] = 0
    heappush( que,(0,s) )
    while len(que)>0:
        p =  heappop(que)
        v = p[1]
        if d[v] < p[0]:
            continue
        for i in range(len(g[v])):
            edge = g[v][i]
            if d[edge[0]] > d[v] + edge[1]:
                d[edge[0]] = d[v] + edge[1]
                heappush( que,(d[edge[0]] , edge[0]) )
    return d[to-1]

def main():
    n,graph = graphm()
    q,k = inpm()
    for _ in range(q):
        x,y = inpm()
        print( dijkstra(x,k,n,graph) + dijkstra(k,y,n,graph) )    

if __name__ == "__main__":
    main()


Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import Counter,defaultdict,deque
import sys
import bisect
import math
import itertools
import string
import queue
import copy
import random
from heapq import heappop, heappush
#input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def inp(): # n=1
    return int(input())
def inpm(): # x=1,y=2
    return map(int,input().split())
def inpl(): # a=[1,2,3,4,5,...,n]
    return list(map(int, input().split()))
def inpls(): # a=['1','2','3',...,'n']
    return list(input().split())
def inplm(n): # x=[] 複数行
    return list(int(input()) for _ in range(n))
def inpll(n): # [[1,1,1,1],[2,2,2,2],[3,3,3,3]]
    return sorted([list(map(int, input().split())) for _ in range(n)])
def graphm():
    n=inp()
    g=[[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=inpm()
        a-=1
        b-=1
        g[a].append((b,w))
        g[b].append((a,w))
    return n,g
def dijkstra(s,to,n,g): # sからの最短距離 頂点数n
    s -= 1
    que = []
    d = [10**15 for _ in range(n)]
    d[s] = 0
    heappush( que,(0,s) )
    while len(que)>0:
        p =  heappop(que)
        v = p[1]
        if d[v] < p[0]:
            continue
        for i in range(len(g[v])):
            edge = g[v][i]
            if d[edge[0]] > d[v] + edge[1]:
                d[edge[0]] = d[v] + edge[1]
                heappush( que,(d[edge[0]] , edge[0]) )
    return d[to-1]

def main():
    n,graph = graphm()
    q,k = inpm()
    for _ in range(q):
        x,y = inpm()
        print( dijkstra(x,k,n,graph) + dijkstra(k,y,n,graph) )    

if __name__ == "__main__":
    main()


Fixed submission:
from collections import Counter,defaultdict,deque
import sys
import copy
from itertools import permutations, combinations
from heapq import heappop, heappush
input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n=int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n-1):
        a,b,w=map(int,input().split())
        a-=1
        b-=1
        graph[a].append((b,w))
        graph[b].append((a,w))
    graph = tuple(graph)
    q,k = map(int,input().split())
    que = deque([k-1])
    dis = [-1 for _ in range(n)]
    dis[k-1]=0
    while que:
        i = que.pop()
        for j in range(len(graph[i])):
            go = graph[i][j][0]
            d = graph[i][j][1]
            if dis[go]==-1:
                dis[go] = dis[i] + d
                que.append(go)
    for _ in range(q):
        x,y = map(int,input().split())
        print( dis[x-1] + dis[y-1] ) 

if __name__ == "__main__":
    main()