CodeForces 534C - Polycarpus' Dice（思路）

#include<cstdio>  
#include<cstring>  
#include<cctype>  
#include<cstdlib>  
#include<cmath>  
#include<iostream>  
#include<sstream>  
#include<iterator>  
#include<algorithm>  
#include<string>  
#include<vector>  
#include<set>  
#include<map>  
#include<deque>  
#include<queue>  
#include<stack>  
#include<list>  
typedef long long ll;  
typedef unsigned long long llu;  
const int MAXN = 100 + 10;  
const int MAXT = 200000 + 10;  
const int INF = 0x7f7f7f7f;  
const double pi = acos(-1.0);  
const double EPS = 1e-6;  
using namespace std;  
  
int n;  
ll a[MAXT], A;  
  
  
  
int main(){  
    scanf("%d%I64d", &n, &A);  
    ll allsum = 0;                      //所有骰子最大值加起来的总最大值  
    for(int i = 0; i < n; ++i){  
        scanf("%I64d", a + i);  
        allsum += a[i];  
    }  
    for(int i = 0; i < n; ++i){  
        ll down = max(1ll, A - (allsum - a[i]));    //骰子最小值 = 需要的和 - 其他骰子已经全部最大的值  
        ll up = min(a[i], A - (n - 1));             //骰子最大值 = 需要的和 - 其他骰子全部最小值  
        if(i)  printf(" ");  
        printf("%I64d", a[i] - (up - down + 1));    //不可能出现的数 = 总共可以表示的数 - 已经能表示的数  
    }  
    return 0;  
}