Kth Largest Element in an Array - LeetCode

examination questions

Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.

For example,
Given [3,2,1,5,6,4] and k = 2, return 5.

Note:
You may assume k is always valid, 1 ≤ k ≤ array's length.

Please use the following function to solve the problem：

int findKthLargest(int* nums, int numsSize, int k) {

}

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解法1：选择排序

解题代码

int findKthLargest(int* nums, int numsSize, int k) {
    
    int temp;
    for (int i = 0; i < numsSize-1; i++){
        for (int j = i+1; j < numsSize; j++){
            if (nums[i]> nums[j]){
                temp = nums[j];
                nums[j] = nums[i];
                nums[i] = temp;
            }
        }
    }
    return nums[numsSize - k];

}

LeetCode判断结果：

 

解法2：插入排序

解题代码

int findKthLargest(int* nums, int numsSize, int k) {
    
    int *tempArray = (int *)malloc(sizeof(int)*numsSize);
    memset(tempArray,0,sizeof(int)*numsSize);

    for (int i = 0; i < numsSize; i++){
        for (int j = 0; j < numsSize; j++){
            if (nums[i]>tempArray[j]){
                int b = numsSize - j;
                for (int t = 0; t <= b; t++){
                    tempArray[numsSize-t] = tempArray[numsSize-t-1];
                }
                tempArray[j] = nums[i];
                break;
            }
        }
    }
    return tempArray[k-1];
}

LeetCode判断结果：

不知为何会出现这样的错误？代码在本机测试正常。

 

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其他算法分析有时间再添加。