POJ 2456 Aggressive cows

二分答案+贪心

#include <iostream>
#include <algorithm>

using namespace std;

const int MAXN=100111;
const int INF=1034567890;

int N, M;
int Num[MAXN];
int Left, Right, Mid;

bool Test(int k){
    int l=M;
    for(int i=1, p=-k;i<=N;++i){
        if(Num[i]-p>=k){
            --l;p=Num[i];
        }
    }
    return l<=0;
}

int main(){
    ios_base::sync_with_stdio(false);
    
    while(cin >> N >> M){
        for(int i=1;i<=N;++i){
            cin >> Num[i];
        }
        sort(Num+1, Num+N+1);
        Left=0;Right=INF;
        while(Left<Right){
            Mid=(Left+Right)>>1;
            if(Test(Mid+1)) Left=Mid+1;
            else    Right=Mid;
        }
        Mid=(Left+Right)>>1;
        cout << Mid << endl;
    }
    
    return 0;
}