单源最短路径

#include <iostream>
using namespace std;

const static int MAX = 100;
const static int INFIT = 1000;
const static int WHITE = 0;
const static int GRAY = 1;
const static int BLACK = 2;

//用来表示图规模
int graph[MAX][MAX];
int n;

void dijkstra() {
    int minv;
    int d[MAX];
    int color[MAX];
    int u;

    for(int i=0; i<n; i++) {
        d[i] = INFIT;
        color[i] = WHITE;
    }

    d[0] = 0;
    color[0] = GRAY;

    //找到当前最小点
    while(1) {
        minv = INFIT;
        u = -1;
        for(int i=0; i<n; i++) {
            if(color[i] != BLACK && d[i] < minv ){
                minv = d[i];
                u = i;
            }
        }
        //点孤立或点循环完
        if(u==-1) break;
        color[u] = BLACK;

        //更新周围点
        for(int i=0; i<n; i++) {
            if(color[i] != BLACK) {
                if(d[i] > d[u] + graph[u][i]) {
                    d[i] = d[u] + graph[u][i];
                    color[i] = GRAY;
                }
            }
        }
    }
    for(int i=0; i<n; i++) {
        printf("%d %d\n", i, (d[i] == INFIT)? -1 :d[i]);
    }
}

int main() {
    cin >> n;
    for(int i=0; i<n; i++) {
        for(int j=0; j<n; j++) {
            graph[i][j] = INFIT;
        }
    }
    int n1, n2, n3, n4;
    for(int i=0; i<n; i++) {
        cin >> n1 >> n2;
        for(int i=0; i<n2; i++) {
            cin >> n3 >> n4;
            graph[n1][n3] = n4;
        }
    }

    dijkstra();

    return 0;
}