존못코딩

#include <stdio.h>
#include <queue>
#include <vector>
#include <memory.h>
#include <algorithm>
using namespace std;
 
struct dot { int x, y; 
bool operator < (const dot& A)const {
    return y > A.y;  
}}A, B;
int goal[2][1001];
int main()
{
    int n, m, x;
    scanf("%d %d %d", &n, &m, &x);
    vector < vector <dot> > vec(n + 3),vec2(n+1);
    for (int i = 0,a,b,c; i < m; i++)
    {
        scanf("%d %d %d", &a, &b, &c);
        vec[a].push_back({ b, c });
        vec2[b].push_back({ a, c });
    }
    vector <vector <int> >dist(2, vector(n + 1, -1));
    for (int q = 0; q < 2; q++)
    {
        vector <bool>chk(n + 1, false);
        dist[q][x] = 0;
        priority_queue<dot> que;
        que.push({x, 0});
 
        while (!que.empty())
        {
            A = que.top();que.pop();
            chk[A.x] = true;
            if (q == 0)
            {
                for (int i = 0; i < vec[A.x].size(); i++)
                {
                    B = vec[A.x][i];
                    if (chk[B.x])continue;
                    if (dist[0][B.x] == -1 || dist[0][B.x] > dist[0][A.x] + B.y)
                    {
                        dist[0][B.x] = dist[0][A.x] + B.y;
                        que.push({ B.x, dist[0][B.x] });
                    }
                }
            }
            else {
                for (int i = 0; i < vec2[A.x].size(); i++)
                {
                    B = vec2[A.x][i];
                    if (chk[B.x])continue;
                    if (dist[1][B.x] == -1 || dist[1][B.x] > dist[1][A.x] + B.y)
                    {
                        dist[1][B.x] = dist[1][A.x] + B.y;
                        que.push({ B.x, dist[1][B.x] });
                    }
                }
            }
        }
    }
    int M = 0;
    for (int i = 1; i <= n; i++)
        M = max(M, dist[0][i] + dist[1][i]);
 
    printf("%d\n", M);
 
    return 0;
}