求最大子串和

#include <iostream>

using namespace std;

int max(int x, int y)
{
    return x > y ? x : y;
}

int MaxSum(int* a, int n)
{
    int i, res;
    int* start = new int[n];
    int* all = new int[n];
    start[n - 1] = a[n - 1];
    all[n - 1] = a[n - 1];
    for(i = n - 2; i >= 0; i--)
    {
        start[i] = max(a[i], a[i] + start[i + 1]);
        all[i] = max(start[i], all[i + 1]);
    }
    res = all[0];
    delete[] start;
    delete[] all;
    return res;
}

int MyMaxSum(int* a, int n)
{
    int i;
    int max, sum;
    sum = 0;
    max = 1 << 31;
    for(i = 0; i < n; i++)
    {
        if(sum > 0) sum += a[i];
        else sum = a[i];
        if(sum > max) max = sum;
    }
    return max;
}

int main()
{
    int arr[] = {-2, 2, 4, 3, 2, 1, -3, -2, -1, 1, 2, 3, 0, -2};
    cout << MaxSum(arr, sizeof(arr) / sizeof(int)) << endl;
    cout << MyMaxSum(arr, sizeof(arr) / sizeof(int)) << endl;
    return 0;
}

转载于:https://www.cnblogs.com/dashublog/p/3385048.html