題解—HDU 2544 最短路 ( bellman-ford )

最短路基礎題，使用bellman-ford

struct edge e[1e5] 不是鄰接表，只是簡單存圖。

題目連接：https://cn.vjudge.net/problem/HDU-2544

#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
#include <queue>

using namespace std;
typedef long long ll;

const int INF = 1e9 + 7;
const int Max = 10005;

int n, m, sum, cnt;

struct edge
{
    int from, to, value;
}e[Max];

//vector<edge>e[Max];

void bellman_ford()
{
    int s = 1;
    int d[105];
    for (int i = 1; i <= n; i++) d[i] = INF;
    d[s] = 0;
    for (int k = 1; k <= n; k++)
    {
        for (int i = 0; i < cnt; i++)
        {
            int x = e[i].from; int y = e[i].to;
            if (d[x] > d[y] + e[i].value)
            {
                d[x] = d[y] + e[i].value;
            }
        }
    }
    sum = d[n];
}

int main()
{
    while (cin >> n >> m)
    {
        if (n == 0 && m == 0) break;
        cnt = 0, sum = 0;
        for (int i = 1; i <= m; i++)
        {
            int u, v, w;
            cin >> u >> v >> w;
            e[cnt].from = u; e[cnt].to = v; e[cnt].value = w; cnt++;
            e[cnt].from = v; e[cnt].to = u; e[cnt].value = w; cnt++;
        }
        bellman_ford();
        cout << sum << endl;
    }
    return 0;
}