Hdu 2527 Safe Or Unsafe

 

类似HuffMan编码。

CODE：

 

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <queue>
using namespace std;

#define MAXN 1001
priority_queue<int , vector<int>, greater<int> > q;

char str[MAXN];
int huf[MAXN];
int n;

void solve()
{
    int ans = 0, a, b;
    while(q.size() != 1)
    {
        a = q.top(); q.pop();
        b = q.top(); q.pop();
        q.push(a+b);
        ans += (a+b);
    }
    printf(ans <= n?"yes\n":"no\n");
}

void init()
{
    while(!q.empty()) q.pop();
    memset(huf, 0, sizeof(huf));
}

int main()
{
    int T;
    scanf("%d", &T);
    while(T--)
    {
        init();
        scanf("%d", &n);
        scanf("%s", str);
        for(int i = 0; str[i]; i++)
        {
            huf[str[i]-'a']++;
        }
        for(int i = 0; i < 26; i++) if(huf[i])
        {
            q.push(huf[i]);
        }
        if(q.size() == 1)
        {
            int a = q.top(); q.pop();
            printf(a <= n?"yes\n":"no\n");
            continue;
        }
        solve();
    }
    return 0;
}