Erasing and Winning UVA - 11491 贪心

题目：题目链接

思路：不难发现，要使整体尽量大，应先满足高位尽量大，按这个思路优先满足高位即可

AC代码：

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 #include <string>
 #include <vector>
 #include <map>
 #include <set>
 #include <queue>
 #include <deque>

 #define FRER() freopen("in.txt", "r", stdin)
 #define FREW() freopen("out.txt", "w", stdout)

 #define INF 0x3f3f3f3f

 using namespace std;

 const int maxn = 1e5 + ;

 char s[maxn], ans[maxn];

 int main()
 {
     //FRER();
     //FREW();
     ios::sync_with_stdio();
     cin.tie();

     int n, d, m, idx;
     while(cin >> n >> d && (n || d)) {
         cin >> s;
         m = n - d;
         idx = ;
         ans[idx] = s[];
         for(int i = ; i < n; ++i) {
             while(d && idx >=  && ans[idx] < s[i]) {
                 --idx;
                 --d;
             }
             ans[++idx] = s[i];
         }
         ans[m] = '\0';
         cout << ans << endl;
     }
     return ;
 }