POJ 1502 MPI Maelstrom

题目大意:计算从1开始到其他点的最大距离，主要是输入比较扯拐，是邻接矩阵的下三角

解题思路:Dijkstra，思路是Dijkstra模板题，但是，输入比较扯拐

#include <iostream>
#include <cstring>
#include <algorithm>
#define MAXVERTEXNUM 110
#define INF 1000000
using namespace std;

int MGraph[MAXVERTEXNUM][MAXVERTEXNUM];
int dist[MAXVERTEXNUM];
int Nv;

void Dijkstra()
{
    int res = 0;
    int collected[MAXVERTEXNUM];
    memset(collected, 0, sizeof(collected));

    collected[1] = 1;
    dist[1] = 0;
    for (int i = 2; i <= Nv; ++i)
    {
        if (MGraph[i][1] != INF)
            dist[i] = MGraph[i][1];
        else
            dist[i] = INF;
    }

    for (int i = 2; i <= Nv; ++i)
    {
        int MinDis = INF, num;
        for (int j = 2; j <= Nv; ++j)
            if (!collected[j] && dist[j] < MinDis)
            {
                MinDis = dist[j];
                num = j;
            }
        if (res < dist[num])
            res = dist[num];
        collected[num] = 1;

        for (int j = 2; j <= Nv; ++j)
        {
            if (!collected[j] && dist[j] > dist[num] + MGraph[num][j])
                dist[j] = dist[num] + MGraph[num][j];
        }
    }

    cout << res << endl;
}

int main()
{
    ios::sync_with_stdio(false);

    cin >> Nv;

    //init
    for (int i = 1; i <= Nv; ++i)
        for (int j = 1; j <= Nv; ++j)
        {
            if (i == j)
                MGraph[i][j] = 0;
            else
                MGraph[i][j] = INF;
        }

    for (int i = 2; i <= Nv; ++i)
        for (int j = 1; j < i; ++j)
        {
            char Edge[1000];
            memset(Edge, 0, sizeof(Edge));
            cin >> Edge;
            int num = 0;
            if (Edge[0] != 'x')
            {
                for (int i = 0; Edge[i] != ''; ++i)
                    num = num * 10 + Edge[i] - '0';
            }
            else
            {
                MGraph[i][j] = MGraph[j][i] = INF;
                continue;
            }

            MGraph[i][j] = MGraph[j][i] = num;
        }

    Dijkstra();

    return 0;
}