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最新推荐文章于 2020-02-23 19:24:33 发布

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最新推荐文章于 2020-02-23 19:24:33 发布

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分类专栏：最小生成树

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开始用float错 用double对；；


#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
const double _max = 99999999.0;
const int maxn = 111;
double map[maxn][maxn];
bool visit[maxn];
double dist[maxn];
int n, k;
double sum, _min;

struct node
{
    int x;
    int y;
} pi[111];

void prim()
{
    for(int i = 1; i <= n; i++)
        dist[i] = map[1][i];
    dist[1] = 0.0;
    visit[1] = true;
    sum = 0.0;
    for(int i = 1; i < n; i++)
    {
        _min = _max;
        for(int j = 1; j <= n; j++)
            if(!visit[j] && dist[j] < _min)
            {
                _min = dist[j];
                k = j;
            }
        visit[k] = true;
        sum += _min;

        for(int j = 1; j <= n; j++)
            if(!visit[j] && dist[j] > map[k][j] )
                dist[j] = map[k][j];
    }
    if(sum < _max) printf("%.1lf\n", sum*100);
    else printf("oh!\n");
}

int main()
{
    int t;
    scanf("%d", &t);
    while(t--)
    {
        scanf("%d", &n);
        for(int i = 1; i <= n; i++)
            for(int j = 1; j <= n; j++)
                if(i == j) map[i][j] = 0.0;
                else map[i][j] = _max;
        for(int i = 1; i <= n; i++)
            scanf("%d %d", &pi[i].x, &pi[i].y);
        for(int i = 1; i <= n; i++)
        {
            for(int j = i+1; j <= n; j++)
            {
                    int ss = (pi[i].x-pi[j].x)*(pi[i].x-pi[j].x)+(pi[i].y-pi[j].y)*(pi[i].y-pi[j].y);
                    double s = sqrt(double(ss));
                    if(s >= 10.0 && s <= 1000.0 && map[i][j] > s)  map[i][j] = map[j][i] = s;
            }
        }
        memset(visit, false, sizeof(visit));
        prim();
    }
}