c_cpp Dijkstra算法

Posted 2021-05-14

#include <iostream>
using namespace std;
const int N = 7;
const int INF = 1e3;

int g[N][N] = {
	{ INF, 2, INF, 2,4, 3, INF },
	{ 2, INF, 2, INF, INF, 1, INF },
	{ INF, 2, INF, 2, INF, INF, 2 },
	{ 2, INF, 2, INF, 3, INF, INF },
	{ 4, INF, INF, 3, INF, 1, INF },
	{ 3, 1, INF, INF, 1, INF, 2 },
	{ INF, INF, 2,INF, INF, 2, INF } };
int dis[N], vis[N];

void dijkstra(int s) {
	vis[s] = 1;
	for (int i = 0; i < N; i++) {
		dis[i] = g[s][i];
	}
	for (int i = 0; i < N; i++) {
		int pos = 0, Min = INF;
		for (int j = 0; j < N; j++) {
			if (!vis[j] && dis[j] < Min) {
				pos = j;
				Min = dis[pos];
			}
		}
		if (pos) {
			vis[pos] = 1;
			for (int j = 0; j < N; j++) {
				if (j != s && dis[pos] + g[pos][j] < dis[j]) {
					dis[j] = dis[pos] + g[pos][j];
				}
			}
		}
	}
}

int main() {
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < N; j++) {
			cout << g[i][j] << " ";
		}
		cout << endl;
	}
	// 1000 2 1000 2 4 3 1000
	// 2 1000 2 1000 1000 1 1000
	// 1000 2 1000 2 1000 1000 2
	// 2 1000 2 1000 3 1000 1000
	// 4 1000 1000 3 1000 1 1000
	// 3 1 1000 1000 1 1000 2
	// 1000 1000 2 1000 1000 2 1000
	dijkstra(4);
	for (auto v : dis) {
		cout << v << " ";
	}
	cout << endl;
	// 4 2 4 3 1000 1 3
	return 0;
}