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84. Largest Rectangle in Histogram
Hard
Given an array of integers heights representing the histogram’s bar height where the width of each bar is 1, return the area of the largest rectangle in the histogram.
Example 1:
Input: heights = [2,1,5,6,2,3]
Output: 10
Explanation: The above is a histogram where width of each bar is 1. The largest rectangle is shown in the red area, which has an area = 10 units.
Example 2:
Input: heights = [2,4]
Output: 4
Constraints:
1 <= heights.length <= 1050 <= heights[i] <= 104
Solution
public class Solution {
public int LargestRectangleArea(int[] heights) {
int maxArea = 0, i = 0;
Stack<int> stack = new Stack<int>();
while (i <= heights.Length) {
var currHeight = i == heights.Length ? 0 : heights[i];
if (!stack.Any() || currHeight >= heights[stack.Peek()]) {
stack.Push(i);
i++;
}
else {
int index = stack.Pop();
int height = heights[index];
int width = (!stack.Any()) ? i : (i - 1) - stack.Peek();
maxArea = Math.Max(maxArea, height * width);
}
}
return maxArea;
}
}