Leetcode--Maximum Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.

For example, given the array [−2,1,−3,4,−1,2,1,−5,4],
the contiguous subarray [4,−1,2,1] has the largest sum = 6.

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More practice:

If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.

解题思路：对A[0]、A[1]...A[n-1]这n个数中求连续子集的最大值

对A[1]、A[2]...A[n-1]  中最大和为All[1],包含A[1]的最大和为Start[1]

那么，All[0]=MAX{A[0],A[0]+Start[1],All[1]}

这里的划分：A[0]与最大和数组有无关系，或者说最大和数组包含不包含A[0]

算法思想是动态规划，从后往前，不去计算已经算过的东西，即“去除冗余”

class Solution {public:    int maxSubArray(int A[], int n) {        //A[0]        //A[1]...A[n-1]  最大和为All[1]         //包含A[1]的最大的和为Start[1]        if(n<=0)            return 0;        int All,Start;        All=Start=A[n-1];        for(int i=n-2;i>=0;i--)        {            if(A[i]+Start>A[i])                Start=A[i]+Start;            else                Start=A[i];                            if(Start>All)                All=Start;        }        return All;    }};