题目：

题解：

/*** 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().*/
struct vat
{int start;int end;
};int compare(struct vat* a,struct vat  *b)
{return a->start - b->start;
}int** merge(int** intervals, int intervalsSize, int* intervalsColSize, int* returnSize, int** returnColumnSizes)
{struct vat newVat[intervalsSize];for(int i =0; i < intervalsSize; i++){newVat[i].start = intervals[i][0];newVat[i].end   = intervals[i][1];}qsort(newVat,intervalsSize,sizeof(struct vat),compare);int **returnInteval = (int **)malloc(sizeof(int *) * intervalsSize);*returnColumnSizes  = (int *)malloc(sizeof(int ) * intervalsSize);*returnSize = 0;for(int i =0; i < intervalsSize; i++){if(*returnSize){int preEnd = returnInteval[*returnSize-1][1];if(newVat[i].start <= preEnd){//合并int  maxEnd = fmax(preEnd,newVat[i].end);returnInteval[*returnSize-1][1] = maxEnd;}else{//没有重合的int newRow = *returnSize;returnInteval[newRow]   = (int *)malloc(sizeof(int ) * 2);returnInteval[newRow][0] =  newVat[i].start;returnInteval[newRow][1] =  newVat[i].end;(*returnColumnSizes)[newRow] = 2;*returnSize = *returnSize + 1;}}else{int newRow = *returnSize;returnInteval[newRow]   = (int *)malloc(sizeof(int ) * 2);returnInteval[newRow][0] =  newVat[i].start;returnInteval[newRow][1] =  newVat[i].end;(*returnColumnSizes)[newRow] = 2;*returnSize = *returnSize + 1;}}return returnInteval;
}