Bellman-Ford_檢測負權迴路 ---- 啊哈演算法
阿新 • • 發佈:2019-02-02
//
// Created by jal on 18-9-3.
//
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 50, MAXM = 10000, MAX = 99999;
int u[MAXM], v[MAXM], w[MAXM], dis[MAXN];
int n, m;
void init() {
cin >> n >> m;
for (int i = 1; i <= n; i++) {
dis[i] = MAX;
}
dis[1] = 0 ;
for (int i = 1; i <= m; i++) {
cin >> u[i] >> v[i] >> w[i];
}
}
int main() {
init();
//Bellman演算法核心語句 4句
for (int k = 1; k < n; k++) {
for (int i = 1; i <= m; i++) {
if (dis[v[i]] > dis[u[i]] + w[i]) {
dis[v[i]] = dis[u[i]] + w[i];
}
}
}
int flag = 0;
for(int i = 1; i <= m; i++){
if (dis[v[i]] > dis[u[i]] + w[i]) {
flag = 1;
}
}
if(flag){
cout << "此圖含有負權迴路!" << endl;
} else{
cout << "此圖不含負權迴路!" << endl;
for(int i = 1; i <= n; i++){
cout << dis[i] << " ";
}
cout << endl;
}
}
/*
input:
6 9
1 2 1
1 3 12
2 3 9
2 4 3
3 5 5
4 3 4
4 5 13
4 6 15
5 6 4
output:
此圖不含負權迴路!
0 1 8 4 13 17
input:
5 5
2 3 2
1 2 -3
1 5 5
4 5 2
3 4 3
output:
此圖不含負權迴路!
0 -3 -1 2 4
*/