hdu 1596 最短路

直接上代码

/*
 * hdu1596/win.cpp
 * Created on: 2011-12-5
 * Author    : ben
 */
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <iostream>
#include <algorithm>
using namespace std;
typedef double typec;
const int SIZE = 1005;
const typec MAX = 0;
typec map[SIZE][SIZE];
int N;
typec dijistra(int s, int e) {
    int i, j, k;
    typec mind, D[SIZE];
    bool visited[SIZE];
    for (i = 0; i < N; i++) {
        visited[i] = false;
        D[i] = map[s][i];
    }
    visited[s] = 1;
    D[s] = 1;
    for (i = 1; i < N; i++) {
        mind = MAX;
        k = 0;
        for (j = 0; j < N; j++) {
            if (visited[j]) {
                continue;
            }
            if (D[j] > mind) {
                k = j;
                mind = D[j];
            }
        }
        visited[k] = true;
        for (j = 0; j < N; j++) {
            if (!visited[j]) {
                if (D[k] * map[k][j] > D[j]) {
                    D[j] = D[k] * map[k][j];
                }
            }
        }
    }
    return D[e];
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int Q, a, b;
    typec ret;
    while (scanf("%d", &N) == 1) {
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < N; j++) {
                scanf("%lf", &map[i][j]);
            }
        }
        scanf("%d", &Q);
        while (Q--) {
            scanf("%d%d", &a, &b);
            ret = dijistra(a - 1, b - 1);
            if(ret <= 0) {
                puts("What a pity!");
            }else {
                printf("%.3f\n", ret);
            }
        }
    }
    return 0;
}