【力扣 - 除自身以外数组的乘积】-题解

解题思路

左右乘积表，分别计算i左侧和右侧乘积。

代码

/**
 * Note: The returned array must be malloced, assume caller calls free().
 */

// Function to compute the product of all elements in the input array except the current element
int* productExceptSelf(int* nums, int numsSize, int* returnSize) {
    // Arrays to store the product of elements to the left and right of each element
    int leftProduct[numsSize];
    int rightProduct[numsSize];
    
    // Calculate the product of elements to the left of each element
    leftProduct[0] = 1;
    for (int i = 1; i < numsSize; i++) {
        leftProduct[i] = leftProduct[i - 1] * nums[i - 1];
    }
    
    // Calculate the product of elements to the right of each element
    rightProduct[numsSize - 1] = 1;
    for (int j = numsSize - 2; j >= 0; j--) {
        rightProduct[j] = rightProduct[j + 1] * nums[j + 1];
    }
    
    // Set the return size for the caller
    *returnSize = numsSize;
    
    // Compute the final product array by multiplying left and right products
    int* Answer = (int*)malloc(sizeof(int) * numsSize);
    for (int k = 0; k < numsSize; k++) {
        Answer[k] = leftProduct[k] * rightProduct[k];
    }
    
    return Answer;
}