Max Sum
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 286615 Accepted Submission(s): 68051
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
参考求最大子序列,只要处理一下输入输出以及一些细节即可,竞赛题细节很重要,培养了参赛选手的细心程度。
#include <iostream>
//采用动态规划,用数组也是可以的,但容易超时
using namespace std;
int main()
{
int T, N, sum, max, a, i, j, left, z, right;
cin >> T;
for(i = 0; i < T; i++)
{
cin >> N;
for(left = z = right = sum = 0, max = -1001, j = 0; j < N; j++)
{
cin >> a;
sum += a;
if(max < sum)
{
left = z;
right = j;
max = sum;
}
if(sum < 0)
{
z = j + 1;
sum = 0;//当总和小于0时就抛弃前面的值
}
}
cout << "Case " << i + 1 << ":" << endl;
cout <<max << " " << ++left << " " << ++right << endl;
if(i < T - 1)
cout << endl;
}
return 0;
}