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79 lines
1.6 KiB (Stored with Git LFS)
C++
79 lines
1.6 KiB (Stored with Git LFS)
C++
#include <bits/stdc++.h>
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#define R register int
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#define ll long long
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#define db double
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#define FOR(i, j, k) for (R i = j; i <= k; i++)
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#define DEC(i, j, k) for (R i = j; i >= k; i--)
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#define walk(i, u) for (R i = 0; i < g[u].size(); i++)
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#define visch(i, u) for (R i = head[u]; i; i = edge[i].next)
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using namespace std;
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inline int read() {
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int x = 0;
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bool flag = 0;
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int ch = getchar();
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while ('0' > ch || ch > '9') {
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if (ch == '-')
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flag = 1;
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ch = getchar();
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}
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while ('0' <= ch && ch <= '9') {
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x = (x << 1) + (x << 3) + (ch ^ 48);
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ch = getchar();
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}
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return flag ? -x : x;
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}
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const int maxn = 2510, maxm = 6210;
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int n, m, s, t;
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struct E {
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int to, nxt, w;
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} edge[maxm << 1];
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int head[maxn], ec;
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inline void adde(int u, int v, int w) {
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edge[++ec].to = v;
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edge[ec].nxt = head[u];
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edge[ec].w = w;
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head[u] = ec;
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}
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deque<int> q;
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ll dis[maxn];
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bool vis[maxn];
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inline void spfa() {
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FOR(i, 1, n)
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dis[i] = 0x3f3f3f3f3f3f3f3f;
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dis[s] = 0;
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vis[s] = 1;
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q.push_back(s);
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while (q.size()) {
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int u = q.front();
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q.pop_front();
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vis[u] = 0;
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for (int i = head[u]; i; i = edge[i].nxt) {
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int v = edge[i].to;
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if (dis[u] + edge[i].w < dis[v]) {
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dis[v] = dis[u] + edge[i].w;
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if (!vis[v])
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q.push_back(v);
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}
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}
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}
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}
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int main() {
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n = read(), m = read(), s = read(), t = read();
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FOR(i, 1, m) {
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int x = read(), y = read(), z = read();
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adde(x, y, z);
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adde(y, x, z);
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}
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spfa();
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printf("%lld", dis[t]);
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return 0;
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}
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