Create 2526_xuechelingxiao.cpp

From http://blog.csdn.net/xuechelingxiao/article/details/40680981

POJ/2526_xuechelingxiao.cpp

@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <iostream>
+#include <algorithm>
+using namespace std;
+
+struct Point {
+    double x, y;
+} P[20010], o;
+
+int cmp(Point a, Point b) {
+    if(a.x == b.x)
+        return a.y < b.y;
+    return a.x < b.x;
+}
+
+int main()
+{
+    int n;
+    int T;
+    scanf("%d", &T);
+    while(T--) {
+        bool flag = true;
+        scanf("%d", &n);
+        for(int i = 1; i <= n; ++i) {
+            scanf("%lf%lf", &P[i].x, &P[i].y);
+        }
+        sort(P+1, P+n+1, cmp);
+        o.x = (P[1].x+P[n].x)/2;
+        o.y = (P[1].y+P[n].y)/2;
+        for(int i = 2; i <= n; ++i) {
+            double x = (P[i].x+P[n-i+1].x)/2;
+            double y = (P[i].y+P[n-i+1].y)/2;
+            if(x != o.x || y != o.y) {
+                flag = false;
+                //printf("%d\n", i);
+                break;
+            }
+        }
+        if(flag) {
+            printf("yes\n");
+        }
+        else {
+            printf("no\n");
+        }
+    }
+
+    return 0;
+}