78. Subsets【leetcode】for循环内部和外部的输出的数据不一致，求点拨

Z时代
2024-01-10
分类：IT

使用二进制的方法来解这个问题。但是在subset函数内部，for循环里边，单步输出中间结果是没问题的，但在所有的子集都生成之后，再次输出，结果是不一样的，而且出现了乱码的情况。
测试为{1,2,3,5}
图片描述

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <limits.h>
int cmpfunc (const void * a, const void * b){
   return ( *(int*)a - *(int*)b );
}
int** subsets(int* nums, int numsSize, int** columnSizes, int* returnSize) {
    int size =  1 << numsSize;
    int** rst = (int**)malloc(sizeof(int *) * size); 
    memset(rst,0,sizeof(rst));
    for(int i = 0; i < size; i++) {
        rst[i] = (int*)malloc(sizeof(int)*numsSize);
        memset(rst[i], 0, sizeof(rst[i]));
    }
    qsort( nums, numsSize, sizeof(int), cmpfunc);
    for (int i = 0; i < size; i++) {       
        int len = 0;
        int tmp = i;
        for (int j = 0; (j < numsSize) && tmp; j++) {
           if (tmp & 1) {
               rst[i][len++] = nums[j];
           }
           tmp >>= 1;
        }
            for(int j = 0; j<len;j++) //{}
                   printf("%10d",rst[i][j]);
           printf("\n");
        columnSizes[i] = (int*)malloc(sizeof(int));
        *columnSizes[i] = len;
    } 
    for(int i = 0; i<size;i++){
            for(int j = 0; j<*columnSizes[i];j++) //{}
                   printf("%10d",rst[i][j]);
           printf("\n");
    }
    *returnSize = size;
    return rst;
}
int main(){
    int nums[] = {1,2,3,5};
    int numsSize =4;
    int* size = (int*)malloc(sizeof(int));
    *size = 0;
    int** columnSizes = (int **)malloc(sizeof(int *)); 
    int** rst1 = (int **)malloc(sizeof(int*)*numsSize); 
    memset(rst1,0,sizeof(rst1));
    rst1 = subsets(nums,numsSize,columnSizes,size); 
    int len = 1 << numsSize;;
    printf("%5d\n",*size);
    for (int i = 0; i < *size; i++) {
        //printf("1");
        for (int j = 0; j < *columnSizes[i]; j++) {
          // printf("%5d",rst[i][j]);
        }
       //free(rst[i]);
       // printf("\n");
    }
    //free(rst);
   // printf("%5d\n",a); 
    system("pause"); 
    return 0;
}

回答：

自己写了一下, 通过了leetcode. 供参考.

static int cmpfunc (const void* a, const void* b) {
   return *(int*)a - *(int*)b;
}
int** subsets(int* nums, int numsSize, int** columnSizes, int* returnSize) {
    int i, j, size, tsize;
    int *colSizeArr, *tArr;
    int **subsetpp;
    subsetpp = NULL;
    tArr = (int *)malloc(sizeof(int) * numsSize);
    if (!tArr)
        goto err;
    size = (1 << numsSize);
    *returnSize = size;
    colSizeArr = (int *)malloc(sizeof(int) * size);
    if (!colSizeArr)
        goto err;
    subsetpp = (int **)calloc(size, sizeof(int*));
    if (!subsetpp)
        goto err;
    for (i = 0; i < size; i++) {
        for (tsize = j = 0; j < numsSize; j++)
            if (i & (1 << j))
                tArr[tsize++] = nums[j];
        subsetpp[i] = (int *)malloc(sizeof(int) * tsize);
        if (!subsetpp[i])
            goto err;
        qsort(tArr, tsize, sizeof(int), cmpfunc);
        memcpy(subsetpp[i], tArr, sizeof(int) * tsize);
        colSizeArr[i] = tsize;
    }
    free(tArr);
    *columnSizes = colSizeArr;
    return subsetpp;
err:
    for (i = 0; i < size; i++)
        if (subsetpp[i])
            free(subsetpp[i]);
    if (subsetpp)
        free(subsetpp);
    if (colSizeArr)
        free(colSizeArr);
    if (tArr)
        free(tArr);
    return NULL;}