@@ -474,7 +474,128 @@ class Solution:
474474
475475### Go:
476476
477- > 单调栈
477+ 暴力解法
478+ 479+ ``` go
480+ func largestRectangleArea (heights []int ) int {
481+ sum := 0
482+ for i := 0 ; i < len (heights); i++ {
483+ left , right := i, i
484+ for left >= 0 {
485+ if heights[left] < heights[i] {
486+ break
487+ }
488+ left--
489+ }
490+ for right < len (heights) {
491+ if heights[right] < heights[i] {
492+ break
493+ }
494+ right++
495+ }
496+ w := right - left - 1
497+ h := heights[i]
498+ sum = max (sum, w * h)
499+ }
500+ return sum
501+ }
502+ 503+ func max (x , y int ) int {
504+ if x > y {
505+ return x
506+ }
507+ return y
508+ }
509+ ```
510+ 511+ 双指针解法
512+ 513+ ``` go
514+ func largestRectangleArea (heights []int ) int {
515+ size := len (heights)
516+ minLeftIndex := make ([]int , size)
517+ minRightIndex := make ([]int , size)
518+ 519+ // 记录每个柱子 左边第一个小于该柱子的下标
520+ minLeftIndex[0 ] = -1 // 注意这里初始化,防止下面while死循环
521+ for i := 1 ; i < size; i++ {
522+ t := i - 1
523+ // 这里不是用if,而是不断向左寻找的过程
524+ for t >= 0 && heights[t] >= heights[i] {
525+ t = minLeftIndex[t]
526+ }
527+ minLeftIndex[i] = t
528+ }
529+ // 记录每个柱子 右边第一个小于该柱子的下标
530+ minRightIndex[size - 1 ] = size; // 注意这里初始化,防止下面while死循环
531+ for i := size - 2 ; i >= 0 ; i-- {
532+ t := i + 1
533+ // 这里不是用if,而是不断向右寻找的过程
534+ for t < size && heights[t] >= heights[i] {
535+ t = minRightIndex[t]
536+ }
537+ minRightIndex[i] = t
538+ }
539+ // 求和
540+ result := 0
541+ for i := 0 ; i < size; i++ {
542+ sum := heights[i] * (minRightIndex[i] - minLeftIndex[i] - 1 )
543+ result = max (sum, result)
544+ }
545+ return result
546+ }
547+ 548+ func max (x , y int ) int {
549+ if x > y {
550+ return x
551+ }
552+ return y
553+ }
554+ ```
555+ 556+ 单调栈
557+ 558+ ``` go
559+ func largestRectangleArea (heights []int ) int {
560+ result := 0
561+ heights = append ([]int {0 }, heights...) // 数组头部加入元素0
562+ heights = append (heights, 0 ) // 数组尾部加入元素0
563+ st := []int {0 }
564+ 565+ // 第一个元素已经入栈,从下标1开始
566+ for i := 1 ; i < len (heights); i++ {
567+ if heights[i] > heights[st[len (st)-1 ]] {
568+ st = append (st, i)
569+ } else if heights[i] == heights[st[len (st)-1 ]] {
570+ st = st[:len (st)-1 ]
571+ st = append (st, i)
572+ } else {
573+ for len (st) > 0 && heights[i] < heights[st[len (st)-1 ]] {
574+ mid := st[len (st)-1 ]
575+ st = st[:len (st)-1 ]
576+ if len (st) > 0 {
577+ left := st[len (st)-1 ]
578+ right := i
579+ w := right - left - 1
580+ h := heights[mid]
581+ result = max (result, w * h)
582+ }
583+ }
584+ st = append (st, i)
585+ }
586+ }
587+ return result
588+ }
589+ 590+ func max (x , y int ) int {
591+ if x > y {
592+ return x
593+ }
594+ return y
595+ }
596+ ```
597+ 598+ 单调栈精简
478599
479600``` go
480601func largestRectangleArea (heights []int ) int {
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