HDU——1003 Max Sum

Max Sum

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 302175    Accepted Submission(s): 71712

Problem Description

Given a sequence a[1],a[2],a[3]......a[n], your job is to calculate the max sum of a sub-sequence. For example, given (6,-1,5,4,-7), the max sum in this sequence is 6 + (-1) + 5 + 4 = 14.

 

 

Input

The first line of the input contains an integer T(1<=T<=20) which means the number of test cases. Then T lines follow, each line starts with a number N(1<=N<=100000), then N integers followed(all the integers are between -1000 and 1000).

 

 

Output

For each test case, you should output two lines. The first line is "Case #:", # means the number of the test case. The second line contains three integers, the Max Sum in the sequence, the start position of the sub-sequence, the end position of the sub-sequence. If there are more than one result, output the first one. Output a blank line between two cases.

 

 

Sample Input

2 5 6 -1 5 4 -7 7 0 6 -1 1 -6 7 -5

 

 

Sample Output

Case 1: 14 1 4 Case 2: 7 1 6

 

 

Author

Ignatius.L

 

题目大意：给定一段序列，求和最大的子序列

DP中的水题

 

import java.util.*;
import java.math.*;
public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt(), start = 0, end = 0, step = 1;
        int[] nums = new int[100010];
        while(t-- != 0){
            int n = sc.nextInt(), k = 1, sum = 0, max = -9999999;
            for(int i = 1;i <= n;i++)
                nums[i] = sc.nextInt();
            for(int i = 1;i <= n;i++){
                sum += nums[i];                        //先加上去，再做判定
                if(sum > max){
                    max = sum;
                    start = k;
                    end = i;
                }
                if(sum < 0){
                    sum = 0;
                    k = i + 1;
                }
            }
            if(step != 1)
                System.out.println();
            System.out.println("Case " + step + ":");
            System.out.println(max + " " + start + " " + end);
            step++;
        }
    }
}