hdu 4628 Pieces 状态压缩DP

http://acm.hdu.edu.cn/showproblem.php?pid=4628

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
bool is[1<<17];
int f[1<<17] , n , T , cnt , len;
char ch[22] , s[22];
bool check(int m) {
    cnt = 0;
    for(int i=0;ch[i];i++) {
        if(m & (1<<i)) s[cnt++] = ch[i];
    }
    for(int i=0;i<cnt/2;i++) {
        if(s[i] != s[cnt-1-i]) return false;
    }
    return true;
}
void solve() {
    scanf("%s" , ch);
    memset(is , false , sizeof(is));
    len = strlen(ch);
    n = 1 << len; n -= 1;
    f[n] = 0;
    for(int i=0;i<=n;i++) {
        if(check(i)) is[i] = true;
    }
    for(int i=n-1;i>=0;i--) {
        f[i] = (1<<29);
        for(int j=i+1;j<=n;j = (j+1)|i) {
            if(is[j-i]) {
                f[i] = min(f[i] , f[j] + 1);
            }
        }
    }
    printf("%d\n" , f[0]);
}
int main() {
    scanf("%d" , &T);
    while(T--) {
        solve();
    }
    return 0;
}