77. 组合c

/**
 * Return an array of arrays of size *returnSize.
 * The sizes of the arrays are returned as *returnColumnSizes array.
 * Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
 */
int temp[100];

void dfs(int** array,int n,int k,int* returnSize,int* column,int index,int count){
    if(count>k || index>n+1) return ;
    if(count==k){
        array[*returnSize]=(int*)malloc(sizeof(int)*k);
        for(int i=0;i<k;i++) array[*returnSize][i]=temp[i];
        (*returnSize)++;
        return;
    }
    temp[count]=index; 
    dfs(array,n,k,returnSize,column,index+1,count+1);
    temp[count]=0;
    dfs(array,n,k,returnSize,column,index+1,count);
}

int** combine(int n, int k, int* returnSize, int** returnColumnSizes) {
    *returnSize=0;
    int* column=(int*)malloc(sizeof(int)*200000);
    for(int i=0;i<200000;i++) {
        column[i]=k;
    }
    int** array=(int**)malloc(sizeof(int*)*200000);
    *returnColumnSizes=column;
    dfs(array,n,k,returnSize,column,1,0);
    return array;
}

复试的时候内存也往大里开，以免问题。