You are given an array a1,a2,…,ana1,a2,…,an.
In one operation you can choose two elements aiai and ajaj (i≠ji≠j) and decrease each of them by one.
You need to check whether it is possible to make all the elements equal to zero or not.
The first line contains a single integer nn (2≤n≤1052≤n≤105) — the size of the array.
The second line contains nn integers a1,a2,…,ana1,a2,…,an (1≤ai≤1091≤ai≤109) — the elements of the array.
Print "YES" if it is possible to make all elements zero, otherwise print "NO".
4 1 1 2 2
YES
6 1 2 3 4 5 6
NO
In the first example, you can make all elements equal to zero in 33 operations:
In the second example, one can show that it is impossible to make all elements equal to zero.
#include<stdio.h>
#include<iostream>
#include<algorithm>
#include<string.h>
#include<vector>
#include<cmath>
#include<string>
#include<map>
#include<queue>
using namespace std;
typedef long long ll;
ll num[100001],n;
//priority_queue<ll,vector<ll>,less<ll> > p;
int main(){
while(~scanf("%lld",&n)){
ll sum=0,max_k=-1;
for(ll i=1;i<=n;i++){
scanf("%lld",&num[i]);
sum+=num[i];
max_k=max(max_k,num[i]);
}
//如果总和不是偶数，或者最大值比总和的一半大，不能实现
if(sum%2==1||max_k>sum/2){
printf("NO\n");
continue;
}
else {
printf("YES\n");
continue;
}
}
return 0;
}
// /\ | / |**、
// / \ | / | // / \ |/ | / _____ ____ | /
// /------\ |\ |__/ / \ \ /\ / / \ | /
// / \ | \ | / \ \ / \ / /______\ |/
// / \ | \ | \ / \ / \ / \ |
// / \ | \ | \_____/ \/ \/ \_____ |
/**
* ┏┓ ┏┓
* ┏┛┗━━━━━━━┛┗━━━┓
* ┃ ┃
* ┃ ━ ┃
* ┃ ＞ ＜ ┃
* ┃ ┃
* ┃... ⌒ ... ┃
* ┃ ┃
* ┗━┓ ┏━┛
* ┃ ┃ Code is far away from bug with the animal protecting
* ┃ ┃ 神兽保佑,代码无bug
* ┃ ┃
* ┃ ┃
* ┃ ┃
* ┃ ┃
* ┃ ┗━━━┓
* ┃ ┣┓
* ┃ ┏┛
* ┗┓┓┏━┳┓┏┛
* ┃┫┫ ┃┫┫
* ┗┻┛ ┗┻┛
*/
// warm heart, wagging tail,and a smile just for you!
//
// _ooOoo_
// o8888888o
// 88" . "88
// (| -_- |)
// O\ = /O
// ____/`---‘\____
// .‘ \| |// `.
// / \||| : |||// // / _||||| -:- |||||- // | | \\ - /// | |
// | \_| ‘‘\---/‘‘ | |
// \ .-\__ `-` ___/-. /
// ___`. .‘ /--.--\ `. . __
// ."" ‘< `.___\_<|>_/___.‘ >‘"".
// | | : `- \`.;`\ _ /`;.`/ - ` : | |
// \ \ `-. \_ __\ /__ _/ .-` / /
// ======`-.____`-.___\_____/___.-`____.-‘======
// `=---=‘
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
//
原文：https://www.cnblogs.com/akpower/p/11331023.html