题解 | #三数之和#

/**
 * 
 * @param num int整型一维数组 
 * @param numLen int num数组长度
 * @return int整型二维数组
 * @return int* returnSize 返回数组行数
 * @return int** returnColumnSizes 返回数组列数
 */

#include <malloc.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>

void BubbleSort(int *num, int numLen)
{
    while (numLen > 0) {
        for (int i = 0; i < numLen - 1; i++) {
            if (num[i] > num[i + 1]) {
                int temp = num[i + 1];
                num[i + 1] = num[i];
                num[i] = temp;
            }
        }
        numLen--;
    }
}

int** threeSum(int* num, int numLen, int* returnSize, int** returnColumnSizes )
{
    int **ret = NULL;
    int columnSizes = 0;
    int flag = 0;

    BubbleSort(num, numLen);

    for (int i = 0; i < numLen - 2; i++) {
        for (int j = i + 1; j < numLen - 1; j++) {
            for (int k = j + 1; k < numLen; k++) {
                if (num[i] + num[j] + num[k] == 0) {
                    if (columnSizes > 0) {
                        for (int nn = 0; nn < columnSizes; nn++) {
                            if ((num[i] == ret[nn][0]) &&
                                (num[j] == ret[nn][1]) &&
                                (num[k] == ret[nn][2])) {
                                    flag = 1;
                                    break;;
                            }
                        }
                        if (flag == 1) {
                            flag = 0;
                            continue;
                        }
                    }
                    columnSizes++;
                    ret = (int **)realloc(ret, sizeof(int *) * columnSizes);
                    ret[columnSizes - 1] = (int *)malloc(sizeof(int) * columnSizes);
                    ret[columnSizes - 1][0] = num[i];
                    ret[columnSizes - 1][1] = num[j];
                    ret[columnSizes - 1][2] = num[k];
                }
            }
        }
    };

    *returnColumnSizes = (int *)malloc(columnSizes * sizeof(int));
    *returnSize = columnSizes;
    for (int i = 0; i < columnSizes; i++) {
        (*returnColumnSizes)[i] = 3;
    }
    return  ret;
}