洛谷P1119 灾后重建

 

题目

floyd的一道比较好的题目

 

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
//Mystery_Sky
//
#define maxn 300
#define maxm 1000000
#define INF 0x3f3f3f3f
int road[maxn][maxn];
//int map[maxn][maxn];
int fix[maxm];
int n, m, w, u, v, q, t;
int now;

inline void floyd()
{
    for(int i = 0; i < n; i++) 
        for(int j = 0; j < n; j++) 
            road[i][j] = min(road[i][j], road[i][now] + road[now][j]);
    now++;
}

inline void print()
{
    if(fix[u] > t || fix[v] > t || road[u][v] == INF) printf("-1\n");
    else printf("%d\n", road[u][v]);
}

int main() {
    scanf("%d%d", &n, &m);
    for(int i = 0; i < n; i++) scanf("%d", &fix[i]);
    memset(road, INF, sizeof(road));
    for(int i = 1; i <= n; i++) road[i][i] = 0;
    for(int i = 1; i <= m; i++) {
        scanf("%d%d%d", &u, &v, &w);
        road[u][v] = road[v][u] = w;
    }
    scanf("%d", &q);
    for(int i = 1; i <= q; i++) {
        scanf("%d%d%d", &u, &v, &t);
        while (fix[now] <= t && now < n) floyd();
        print();
    }
    return 0;
}