LeetCode-84.直方图中最大的矩形

一、C实现

1. 参考：https://www.jb51.net/article/217227.htm

2. 实现代码

#include <stdio.h>
#include <string.h>

#define ARRAY_SIZE(arr) (sizeof(arr)/sizeof(arr[0]))

int min_val(int x, int y) { return x < y ? x : y; }
int max_val(int x, int y) { return x > y ? x : y; }

int max_histogram_area(int *arr, int sz)
{
    int i, j, lm, mh, res = arr[0];

    for (i = 0; i < sz; i++) {
        if (i+1 < sz && arr[i] <= arr[i+1]) {
            continue;
        }
        printf("arr[%d]=%d\n", i, arr[i]);
        lm = arr[i];
        for (j = i-1; j >= 0; j--) {
            lm = min_val(lm, arr[j]);
            res = max_val(res, lm * (i - j + 1));
        }
    }

    return res;
}


int main()
{
    int mv;
    //int arr[] = {2,1,5,6,2,3};
    //int arr[] = {2};
    int arr[] = {1, 2, 3, 4, 5};
    
    mv = max_histogram_area(arr, ARRAY_SIZE(arr));

    printf("mv=%d\n", mv);

    return 0;
}