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