118. Yanghui triangle

Given a nonnegative integer numRows, Generate 「 Yang hui triangle 」 Before numRows That's ok .

stay 「 Yang hui triangle 」 in , Each number is the sum of the numbers at the top left and right of it .

Example 1:

Input : numRows = 5
Output : [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]

Example 2:

Input : numRows = 1
Output : [[1]]

The solution code is as follows ：

/** * 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** generate(int numRows, int* returnSize, int** returnColumnSizes){
    
    *returnSize=numRows;
    * returnColumnSizes=(int *)malloc(sizeof(int)*numRows);
    int **re=(int **)malloc(sizeof(int*)*numRows);
    
    int i;
    for(i=0;i<numRows;i++){
    
        (*returnColumnSizes)[i]=i+1;
        re[i]=(int*)malloc(sizeof(int)*(i+1));

    }
int j;
re[0][0]=1;
    for(i=1;i<numRows;i++){
    
        for(j=0;j<i+1;j++){
    
            int a,b;
     // printf("df1");
            if(j==0){
    
                a=0;
            }
            else{
    
                a=re[i-1][j-1];
            }
             // printf("df2");
            if(j==i){
    
                b=0;
            }
            else{
    
                b=re[i-1][j];

            }

            re[i][j]=a+b;
        }
        // printf("df3");


    }
   // printf("dfsdf");
    return re;


}