1 #include <bits/stdc++.h> 2 #define _for(i,a,b) for(int i = (a);i < b;i ++) 3 typedef long long ll; 4 using namespace std; 5 inline ll read() 6 { 7 ll ans = 0; 8 char ch = getchar(), last = ' '; 9 while(!isdigit(ch)) last = ch, ch = getchar(); 10 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar(); 11 if(last == '-') ans = -ans; 12 return ans; 13 } 14 inline void write(ll x) 15 { 16 if(x < 0) x = -x, putchar('-'); 17 if(x >= 10) write(x / 10); 18 putchar(x % 10 + '0'); 19 } 20 int n; 21 int a[100003]; 22 int main() 23 { 24 n = read(); 25 _for(i,0,n) 26 a[i] = read(); 27 28 sort(a,a+n); 29 bool flag = true; 30 ll rnt2 = 0; 31 _for(i,0,n) 32 rnt2 += a[i]; 33 if(rnt2&0x1 || a[n-1]*2>rnt2) 34 flag = false; 35 36 if(flag) 37 printf("YES"); 38 else 39 printf("NO"); 40 return 0; 41 }
数学题，总和为偶数且最大的数不到总和的一半就输出YES