OJ-Problems-Source/HDOJ/4479_autoAC.cpp

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#include <cstdlib>
#include <cstdio>
#include <algorithm>
#include <iostream>
#include <cstring>
using namespace std;
typedef long long LL;
int N, M;
struct Edge {
int x, y, d;
bool operator < (const Edge & ot) const {
return d < ot.d;
}
}e[50005];
const LL INF = 0x3f3f3f3f3f3f3f3fLL;
LL dis[10005];
struct Rec {
int v;
LL d;
}rec[10005];
void update(int l, int r) {
int u, v, d, idx = 0;
for (int i = l; i <= r; ++i) {
u = e[i].x, v = e[i].y, d = e[i].d;
if (dis[u] != INF && dis[v] > dis[u] + d) {
rec[idx].v = v, rec[idx++].d = dis[u] + d;
}
if (dis[v] != INF && dis[u] > dis[v] + d) {
rec[idx].v = u, rec[idx++].d = dis[v] + d;
}
}
for (int i = 0; i < idx; ++i) {
dis[rec[i].v] = min(dis[rec[i].v], rec[i].d);
}
}
void solve() {
memset(dis, 0x3f, sizeof (dis));
dis[1] = 0;
for (int i = 0, j; i < M; i = j) {
for (j = i + 1; j < M; ++j) {
if (e[j].d != e[i].d) break;
}
update(i, j-1);
}
if (dis[N] == INF) puts("No answer");
else printf("%I64d\n", dis[N]);
}
int main() {
int T;
scanf("%d", &T);
while (T--) {
scanf("%d %d", &N, &M);
for (int i = 0; i < M; ++i) {
scanf("%d %d %d", &e[i].x, &e[i].y, &e[i].d);
}
sort(e, e + M);
solve();
}
return 0;
}