规范格式

leetcode/0084.Largest-Rectangle-in-Histogram/84. Largest Rectangle in Histogram.go

@@ -0,0 +1,39 @@
+package leetcode
+
+import "fmt"
+
+func largestRectangleArea(heights []int) int {
+	maxArea, stack, height := 0, []int{}, 0
+	for i := 0; i <= len(heights); i++ {
+		if i == len(heights) {
+			height = 0
+		} else {
+			height = heights[i]
+		}
+		if len(stack) == 0 || height >= heights[stack[len(stack)-1]] {
+			stack = append(stack, i)
+		} else {
+			tmp := stack[len(stack)-1]
+			fmt.Printf("1. tmp = %v stack = %v\n", tmp, stack)
+			stack = stack[:len(stack)-1]
+			length := 0
+			if len(stack) == 0 {
+				length = i
+			} else {
+				length = i - 1 - stack[len(stack)-1]
+				fmt.Printf("2. length = %v stack = %v i = %v\n", length, stack, i)
+			}
+			maxArea = max(maxArea, heights[tmp]*length)
+			fmt.Printf("3. maxArea = %v heights[tmp]*length = %v\n", maxArea, heights[tmp]*length)
+			i--
+		}
+	}
+	return maxArea
+}
+
+func max(a int, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}

leetcode/0084.Largest-Rectangle-in-Histogram/84. Largest Rectangle in Histogram_test.go

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+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question84 struct {
+	para84
+	ans84
+}
+
+// para 是参数
+// one 代表第一个参数
+type para84 struct {
+	one []int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans84 struct {
+	one int
+}
+
+func Test_Problem84(t *testing.T) {
+
+	qs := []question84{
+
+		question84{
+			para84{[]int{2, 1, 5, 6, 2, 3}},
+			ans84{10},
+		},
+
+		question84{
+			para84{[]int{1}},
+			ans84{1},
+		},
+
+		question84{
+			para84{[]int{1, 1}},
+			ans84{2},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 84------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans84, q.para84
+		fmt.Printf("【input】:%v       【output】:%v\n", p, largestRectangleArea(p.one))
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/0084.Largest-Rectangle-in-Histogram/README.md

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+# [84. Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram/)
+
+## 题目
+
+Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.
+
+ ![](https://assets.leetcode.com/uploads/2018/10/12/histogram.png)
+
+
+Above is a histogram where width of each bar is 1, given height = [2,1,5,6,2,3].
+
+![](https://assets.leetcode.com/uploads/2018/10/12/histogram_area.png)
+
+
+The largest rectangle is shown in the shaded area, which has area = 10 unit.
+
+ 
+
+Example:
+
+```c
+Input: [2,1,5,6,2,3]
+Output: 10
+```
+
+
+## 题目大意
+
+给出每个直方图的高度，要求在这些直方图之中找到面积最大的矩形，输出矩形的面积。
+
+
+## 解题思路
+
+用单调栈依次保存直方图的高度下标，一旦出现高度比栈顶元素小的情况就取出栈顶元素，单独计算一下这个栈顶元素的矩形的高度。然后停在这里(外层循环中的 i--，再 ++，就相当于停在这里了)，继续取出当前最大栈顶的前一个元素，即连续弹出 2 个最大的，以稍小的一个作为矩形的边，宽就是 2 计算面积…………如果停在这里的下标代表的高度一直比栈里面的元素小，就一直弹出，取出最后一个比当前下标大的高度作为矩形的边。宽就是最后一个比当前下标大的高度和当前下标 i 的差值。计算出面积以后不断的更新 maxArea 即可。