UVA 10905 Children's Game （贪心）

贪心，假如任意给出一个序列，如果两两交换了以后会变大，那么就交换，直到不能交换为止。

#include<bits/stdc++.h>
using namespace std;
const int maxn = 51;

string s[maxn];
int rk[maxn];
bool cmp(int x,int y)
{
    int i = 0, j = 0, n1 = s[x].size(), n2 = s[y].size();
    string *s1 = &s[x], *s2 = &s[y];
    int ct = n1+n2;
    while(ct--){
        if(i == n1) i = 0,s1 = &s[y];
        if(j == n2) j = 0,s2 = &s[x];
        if(s1->at(i) != s2->at(j)) return s1->at(i) < s2->at(j);
        i++;j++;
    }
    return false;
}


int main()
{
    //freopen("in.txt","r",stdin);
    ios_base::sync_with_stdio(false);
    int n;
    while(cin>>n&&n){
        for(int i = 0; i < n; i++) cin>>s[i], rk[i] = i;
        sort(rk,rk+n,cmp);
        for(int i = n-1; i>=0; i--) printf("%s",s[rk[i]].c_str());
        puts("");
    }
    return 0;
}