【leetcode】401. 二进制手表

void recursion(int* t, int minute, int hour, int n, int cur, int start, char** arr, int* pst){
    if (minute >= 60 || hour >= 12) return;
    if (cur == n){
        char* s = (char*)calloc(10, sizeof(char));
        int len = sprintf(s, "%d:", hour);
        if (minute <10)
            sprintf(s + len, "0%d", minute);
        else{
            sprintf(s + len, "%d", minute);
        }
        arr[(*pst)++] = s;
        return;
    }
    for (int i = start; i <= cur + 10 - n; i++){
        if (i<6)
            recursion(t, minute + t[i], hour, n, cur + 1, i + 1, arr, pst);
        else
            recursion(t, minute, hour + t[i], n, cur + 1, i + 1, arr, pst);
    }
}
char ** readBinaryWatch(int num, int* returnSize){
    int t[] = { 1, 2, 4, 8, 16, 32, 1, 2, 4, 8 };
    char** arr = (char**)calloc(1000, sizeof(char*));
    int pst = 0;
    recursion(t, 0, 0, num, 0, 0, arr, &pst);
    *returnSize = pst;
    return arr;
}