LightOj-1023-Discovering Permutations

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題目傳送門

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題意:輸出A-Z裏面前N個字母的全排列的前K個。

思路:使用next_permutation()函數。

#include <bits/stdc++.h>

using namespace std;

int main(void)
{
    int T,cas=1;
    scanf("%d", &T);
    while (T--)
    {
        int n, k;
        scanf("%d %d", &n, &k);
        char ch[30];
        for (int i = 0; i < n; i++)
            ch[i] = 'A'+i;
        printf("Case %d:\n",cas++);
        do
        {
            if (!k)
                break;
            k--;
            for (int i = 0; i < n; i++)
                printf("%c", ch[i]);
            printf("\n");
        }while (next_permutation(ch, ch+n));
    }
    return 0;
}