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solution of maximum subarray problem

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	`1`	`+// https://leetcode.com/problems/maximum-subarray/`
	`2`	`+// https://en.wikipedia.org/wiki/Maximum_subarray_problem`
	`3`	`+package main`
	`4`	`+`
	`5`	`+func maxSubArray(nums []int) int {`
	`6`	`+ sum := 0`
	`7`	`+ maxSum := -2 << 31`
	`8`	`+`
	`9`	`+ for i := 0; i < len(nums); i++ {`
	`10`	`+ sum = max(nums[i], sum+nums[i])`
	`11`	`+ maxSum = max(sum, maxSum)`
	`12`	`+ }`
	`13`	`+`
	`14`	`+ return maxSum`
	`15`	`+}`
	`16`	`+`
	`17`	`+func max(i, j int) int {`
	`18`	`+ if i > j {`
	`19`	`+ return i`
	`20`	`+ }`
	`21`	`+ return j`
	`22`	`+}`

Lines changed: 38 additions & 0 deletions

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	`1`	`+// https://leetcode.com/problems/maximum-subarray/`
	`2`	`+// https://en.wikipedia.org/wiki/Maximum_subarray_problem`
	`3`	`+// Divide and Conquer approach`
	`4`	`+package main`
	`5`	`+`
	`6`	`+func maxSubArray(nums []int) int {`
	`7`	`+ n := len(nums)`
	`8`	`+ if n == 1 {`
	`9`	`+ return nums[0]`
	`10`	`+ }`
	`11`	`+`
	`12`	`+ mid := (n - 1) / 2`
	`13`	`+`
	`14`	`+ ans := max(maxSubArray(nums[:mid+1]), maxSubArray(nums[mid+1:]))`
	`15`	`+`
	`16`	`+ sum := 0`
	`17`	`+ pLeft := nums[mid]`
	`18`	`+ for i := mid; i >= 0; i-- {`
	`19`	`+ sum += nums[i]`
	`20`	`+ pLeft = max(pLeft, sum)`
	`21`	`+ }`
	`22`	`+`
	`23`	`+ pRight := nums[mid+1]`
	`24`	`+ sum = 0`
	`25`	`+ for i := mid + 1; i < n; i++ {`
	`26`	`+ sum += nums[i]`
	`27`	`+ pRight = max(pRight, sum)`
	`28`	`+ }`
	`29`	`+`
	`30`	`+ return max(ans, pLeft+pRight)`
	`31`	`+}`
	`32`	`+`
	`33`	`+func max(i, j int) int {`
	`34`	`+ if i > j {`
	`35`	`+ return i`
	`36`	`+ }`
	`37`	`+ return j`
	`38`	`+}`

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