uva 1312 Cricket Field

题意：在一块地上有一堆树，找一个最大无树的正方形（边上可以有树）。输出西南端点的横纵坐标及边长。

分析：枚举，扫描

#include<cstdio>
#include<algorithm>
#define maxn 110
using namespace std;

struct Point
{
int x, y;
} p[maxn];
int n, W, H, y[maxn];

bool cmp(const Point a, const Point b)
{
if(a.x == b.x)
return a.y < b.y;
return a.x < b.x;
}

void init()
{
for(int i = 0; i < n; i++)
{
scanf("%d%d", &p[i].x, &p[i].y);
y[i] = p[i].y;
}
y
= 0, y[n + 1] = H;
sort(y, y + n + 2);
sort(p, p + n, cmp);
}

void solve()
{
int ans = 0, xx, yy;
int m = unique(y, y + n + 2) - y;
for(int i = 0; i < m; i++)
for(int j = i + 1; j < m; j++)
{
int h = y[j] - y[i], pre = 0, w;
for(int k = 0; k < n; k++)
{
if(p[k].y <= y[i] || p[k].y >= y[j])
continue;
w = p[k].x - pre;
if(ans < min(w, h))
{
ans = min(w,h);
xx = pre;
yy = y[i];
}
pre = p[k].x;
}
w = W - pre;
if(ans < min(h, w))
{
ans = min(h,w);
xx = pre;
yy = y[i];
}
}
printf("%d %d %d\n",xx, yy, ans);
}

int main()
{
int cas;
scanf("%d", &cas);
while(cas--)
{
scanf("%d%d%d",&n, &W, &H);
init();
solve();
// printf("cas = %d\n",cas);
if(cas)
printf("\n");
}
return 0;
}