poj1146 全排列（STL）

/*
Time:2019.11.5
Author: Goven
type：全排列 
err:
ref:
知识点：1.原型：bool next_permutation(start_pos(迭代器), end_pos(迭代器)) 
          头文件：<algorithm>
          会改变传入参数 
        2.char a[80]; int len = strlen(a); //头文件 <cstring> 
*/
#include<iostream>
#include<algorithm> 
#include<string>
using namespace std;

int main()
{
    string str;
    while (cin >> str && str != "#") {
        int len = str.length();
        int cnt = len - 2;
        while (cnt >= 0 && str[cnt] >= str[cnt + 1]) {
            cnt--;
        }
        if (cnt < 0) cout << "No Successor" << endl;
        else {
            int i;
            for (i = len - 1; i >= 0 && str[i] <= str[cnt]; i--);
            char t = str[cnt];
            str[cnt] = str[i]; 
            str[i] = t;
            reverse(str.begin() + cnt + 1, str.end()); //一开始没有想到，直接翻转就可以，还在想着要重新排序，有点麻烦所以用char做了 
            cout << str << endl;
        }
    } 
    return 0;
}

//char
#include<iostream>
#include<algorithm>
using namespace std;

int main()
{
    char a[55];
    while (cin >> a && a[0] != '#') {
        int len;
        for (len = 0; a[len] != '\0'; len++); 
        int cnt = len - 2;
        while (cnt >= 0 && a[cnt] >= a[cnt + 1]) {
            cnt--;
        }
        if (cnt < 0) cout << "No Successor" << endl;
        else {
            int i;
            for (i = len - 1; i >= 0 && a[i] <= a[cnt]; i--);
            char t = a[cnt];
            a[cnt] = a[i];
            a[i] = t;
            sort(a + cnt + 1, a + len);
            cout << a << endl;
        }
    } 
    return 0;
}

//next_permutation
//ref: https://blog.csdn.net/wyg1997/article/details/50973269 
#include<iostream>
#include<algorithm> 
#include<string>
using namespace std;

int main()
{
    string str;
    while (cin >> str && str != "#") {
        if (next_permutation(str.begin(), str.end())) {
            cout << str << endl;
        } 
        else cout << "No Successor" << endl;
    } 
    return 0;
}