HDU 1015 Safecracker 模拟

题意：在给出的字符串中找一个五大小的序列，使得它符合题目中给出的公式，要求给出字典序最大的。

思路：模拟。我直接暴力枚举，也能过。

http://acm.hdu.edu.cn/showproblem.php?pid=1015

/*********************************************
    Problem : HDU 1015
    Author  : NMfloat
    InkTime (c) NM . All Rights Reserved .
********************************************/

#include <map>
#include <set>
#include <queue>
#include <cmath>
#include <ctime>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>

#define rep(i,a,b)  for(int i = a ; i <= b ; i ++)
#define rrep(i,a,b) for(int i = b ; i >= a ; i --)
#define repE(p,u) for(Edge * p = G[u].first ; p ; p = p -> next)
#define cls(a,x)   memset(a,x,sizeof(a))
#define eps 1e-8

using namespace std;

const int MOD = 1e9+7;
const int INF = 0x3f3f3f3f;
const int MAXN = 1e5+5;
const int MAXE = 2e5+5;

typedef long long LL;
typedef unsigned long long ULL;

int T,n,m,k;
char s[105];
bool cmp(char a1,char a2) {
    return a1 > a2;
}

int g_pow(int num,int ki) {
    int ret = 1;
    rep(i,1,ki) ret *= num;
    return ret;
}

int tr(char a) {
    return a - 'A' + 1;
}

void input() {

}

void solve() {
    int ok = 0;
    int lens = strlen(s);
    sort(s,s+lens,cmp);
    rep(i,0,lens-2) { // 去重
        if(s[i] == s[i+1]) {
            rep(j,i,lens-2) s[i] = s[i+1];
            lens --;
            i --;
        }
    }
    if(lens < 5) {

    }
    else {
        rep(i,0,lens-1) rep(ia,0,lens-1) rep(ib,0,lens-1) rep(ic,0,lens-1) rep(id,0,lens-1) {
            if(i==ia||i==ib||i==ic||i==id||ia==ib||ia==ic||ia==id||ib==ic||ib==id||ic==id) {
                continue;
            }
            if(n == tr(s[i])-g_pow(tr(s[ia]),2)+g_pow(tr(s[ib]),3)-g_pow(tr(s[ic]),4)+g_pow(tr(s[id]),5)) 
            {
                ok =1;
                printf("%c%c%c%c%c\n",s[i],s[ia],s[ib],s[ic],s[id]);
                goto ss;
            }
        }
    }
    ss:
    if(!ok) puts("no solution");
}   

int main(void) {
    //freopen("a.in","r",stdin);
    //scanf("%d",&T); while(T--) {
    //while(~scanf("%d %d",&n,&m)) {
    while(scanf("%d %s",&n,s),n) {
        input();
        solve();
    }
    return 0;
}