Making a String

链接：http://codeforces.com/problemset/problem/624/B

题目：

You are given an alphabet consisting of n letters, your task is to make a string of the maximum possible length so that the following conditions are satisfied:

• the i-th letter occurs in the string no more thana_i times;
• the number of occurrences of each letter in the string must be distinct for all the letters that occurred in the string at least once.

题意：给最多26个字母的出现次序，要求出现次数不同，且每个字母出现的次数不超过所给的次数的最大总数。

分析：贪心，先排个序，从最大的开始考虑，如果相同依次递减。

题解：

#include <iostream>#include <cstdio>#include <cstdlib>#include <algorithm>#include <queue>#include <stack>#include <vector>#include <map>#include <string>#include <cstring>#include <functional>#include <cmath>#include <cctype>#include <cfloat>#include <climits>#include <complex>#include <deque>#include <list>#include <set>#include <utility>using namespace std;int n;int a[27];int main(){//freopen("in.txt","r",stdin);//while(true){cin>>n;for(int i=1;i<=n;i++){cin>>a[i];}sort(a+1,a+n+1);__int64 sum=a[n];for(int i=n-1;i>0;i--){if(a[i]>=a[i+1]&&a[i+1]!=0)a[i]=a[i+1]-1;if(a[i+1]==0)a[i]=0;sum+=(__int64)a[i];}cout<<sum<<endl;//}return 0;}