01-复杂度2 Maximum Subsequence Sum

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本博客介绍了一个算法问题，即寻找给定整数序列中具有最大和的连续子序列，并输出该子序列的最大和及其首尾元素。通过输入整数序列的长度和序列值，输出最大子序列和、首元素和尾元素。

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01-复杂度2 Maximum Subsequence Sum (25分)

Given a sequence of $K$ integers { $N_1$ , $N_2$ , ..., $N_K$ }. A continuous subsequence is defined to be { $N_i$ , $N_{i+1}$ , ..., $N_j$ } where $\le i \le j \le K$ . The Maximum Subsequence is the continuous subsequence which has the largest sum of its elements. For example, given sequence { -2, 11, -4, 13, -5, -2 }, its maximum subsequence is { 11, -4, 13 } with the largest sum being 20.

Now you are supposed to find the largest sum, together with the first and the last numbers of the maximum subsequence.

Input Specification:

Each input file contains one test case. Each case occupies two lines. The first line contains a positive integer $K$ ( $\le 10000$ ). The second line contains $K$ numbers, separated by a space.

Output Specification:

For each test case, output in one line the largest sum, together with the first and the last numbers of the maximum subsequence. The numbers must be separated by one space, but there must be no extra space at the end of a line. In case that the maximum subsequence is not unique, output the one with the smallest indices $i$ and $j$ (as shown by the sample case). If all the $K$ numbers are negative, then its maximum sum is defined to be 0, and you are supposed to output the first and the last numbers of the whole sequence.

Sample Input:

10
-10 1 2 3 4 -5 -23 3 7 -21

Sample Output:

10 1 4

#include <iostream>
#include <stdio.h>
using namespace std;
///1320
int main()
{
    int n;
    int i;
    int t;
    int sum,m;
    int s=0,ee=0,ss=0;
    int first;
    int mark=0;
    int again=1;
    int score[10000];

    sum=m=0;
    scanf("%d",&n);
    for (i=0; i<n; i++)
    {
        scanf("%d",&t);
        if (t>=0)
        {
            mark=1;
        }
        if (i==0)
        {
            first = t;
        }
        if (again==1)
        {
            s=t;
            again=0;
        }
        sum  += t;
        //  sum     = sum<0     ? 0 : sum;
        if (sum>m)
        {
            m=sum;
            ee=t;
            ss=s;
        }
        else if (sum<0)
        {
            sum=0;
            again=1;
        }

    }


    if (mark==0)
    {
        printf("%d %d %d\n",0,first,t);
    }
    else
    {
        printf("%d %d %d\n",m,ss,ee);
    }

    return 0;
}