POJ 1502 MPI Maelstrom

dijkstra  SSIP

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
using namespace std;
const int MAXN = 101;
const int MAXINT = 32767;
int G[MAXN][MAXN];
bool used[MAXN];
int pre[MAXN];
int dist[MAXN]; 

void dijkstra(int n){ 
    for(int i = 1; i <= n; i++){
        dist[i] = G[1][i];
        used[i] = false;
        if( dist[i] != MAXINT )
            pre[i] = 1;
        else
            pre[i] = 0;
    }
    dist[1] = 0; 
    used[1] = true; 
    for(int i = 1; i < n ; i++){
        int min = MAXINT;
        int minIndex = 1;
        for(int j = 1; j <= n; j++){
            if( !used[j] && dist[j] < min){
                min = dist[j];
                minIndex = j;
            }
        }
        used[minIndex] = true;
        for(int j = 1; j <= n; j++){
            if( !used[j] && dist[minIndex] + G[minIndex][j] < dist[j] ){
                dist[j] = G[minIndex][j] + dist[minIndex];
                pre[j] = minIndex;
            }
        }    
    }
}


int main(){
    int n;
    char c[20];
    memset(G,0,sizeof(G));
    scanf("%d",&n);
    for(int i = 2; i <= n; i++){
        for(int j = 1; j < i; j++){
            scanf("%s",c);
            if( strcmp(c,"x")){
                G[i][j] = G[j][i] = atoi(c);
            } else {
                G[i][j] = G[j][i] = MAXINT;
            }
        }
    }
    dijkstra(n);
    int max = dist[1];
    for(int i = 2; i <= n; i++){
        if(max < dist[i])
            max = dist[i];
    }
    printf("%d\n",max);
    return 0;
}