poj1741，【POJ】2454.Jersey Politics

題解

有種迷一樣的諷刺效果
每個城市有1000頭牛，然后你現在知道對于自己政黨每個城市的選票，把城市劃分成三個州，保證在至少兩個州內獲勝

找出前2K大的然后random_shuffle，直到前K個加起來和后K個加起來都滿足超過半數也就是K × 500

代碼

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <ctime>
//#define ivorysi
#define MAXN 305
#define eps 1e-8
#define pb push_back
using namespace std;
typedef long long int64;
typedef unsigned int u32;
typedef double db;
int K;
int a[MAXN],sum,id[MAXN];
bool cmp(int c,int d) {return a[c] > a[d];
}int main() {
#ifdef ivorysifreopen("f1.in","r",stdin);
#endifsrand(20020421);scanf("%d",&K);for(int i = 1 ; i <= 3 * K ; ++i) {id[i] = i;scanf("%d",&a[i]);}sort(id + 1,id + 3 * K + 1,cmp);for(int i = 1 ; i <= 2 * K ; ++i) sum += a[id[i]];while(1) {random_shuffle(id + 1,id + 2 * K + 1);int S = 0;for(int i = 1 ; i <= K ; ++i) S += a[id[i]];if(S > K * 500 && sum - S > K * 500) {for(int i = 1 ; i <= 3 * K ; ++i) {printf("%d\n",id[i]);}return 0;}}
}