1 #include 
     
       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     else39         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