UVa 10245 - The Closest Pair Problem

看着比较简单,但10000的数据量让我TL了两次,需要进一步优化一下,剪一下枝后,AC了,rank还58,惊喜 ~~

代码如下:

#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<cmath>

using namespace std;

struct point
{
    double x, y;
} po[10000 + 2];
int cmp(const void *a, const void *b)
{
    point *aa = (point*)a;
    point *bb = (point*)b;
    return aa ->x > bb->x ? 1 : -1;
}
int main()
{
#ifdef test
    freopen("in.txt", "r", stdin);
#endif
    int t;
    while(scanf("%d", &t), t)
    {
        double min = 10001;
        for(int i = 0; i < t; i++)
            scanf("%lf %lf", &po[i].x, &po[i].y);
        qsort(po, t, sizeof(po[0]), cmp);
        for(int i = 0; i < t; i++)
            for(int j = i + 1; j < t; j++)
            {
                double d1 = po[i].x - po[j].x;
                double d2 = po[i].y - po[j].y;
                double dis = sqrt(d1 * d1 + d2 * d2);
                if(po[j].x - po[i].x >= min)      //在这里剪一下枝
                    break;
                if(dis < min)
                    min = dis;
            }
        if(min >= 10000)
            printf("INFINITY\n");
        else
            printf("%.4lf\n",min);
    }
    return 0;
}


你可能感兴趣的:(优化,pair)