最大子序列和

典型的动态规划问题,递推公式为d[i] = d[i-1] >= 0 ? d[i-1]+a[i] : a[i];
有了递推式,不难列出完整代码:

#include<bits/stdc++.h>
using namespace std;
const int maxn = (int)1e5 + 10;
int arr[maxn], d[maxn];
int main()
{
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; ++i)
        scanf("%d", &arr[i]);
    int ma = arr[0];
    d[0] = arr[0];
    for (int i = 1; i < n; ++i) {
        d[i] = d[i - 1] >= 0 ? d[i - 1] + arr[i] : arr[i];  //核心
        if(d[i] > ma)
            ma = d[i];
    }
    printf("%d\n", ma);
    return 0;
}