LeetCode 84.柱状图中最大的矩形

 

代码如下（Java）：暴力解法

class Solution {
    public int largestRectangleArea(int[] heights) {

        int length = heights.length;
        int[] minLeftIndex = new int[length];
        int[] minRightIndex = new int[length];

        minLeftIndex[0] = -1;

        for(int i = 1; i < length; i++){
            int t = i - 1;
            while(t >= 0 && heights[t] >= heights[i])   t = minLeftIndex[t];
            minLeftIndex[i] = t;
        }

        minRightIndex[length-1] = length;

        for(int i = length - 2; i >= 0; i--){
            int t = i + 1;
            while(t < length && heights[t] >= heights[i])   t = minRightIndex[t];
            minRightIndex[i] = t;
        }

        int result = 0;

        for(int i = 0; i < length; i++){
            int sum = heights[i] * (minRightIndex[i] - minLeftIndex[i] - 1);
            result = Math.max(sum, result);
        }

        return result;
    }
}