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这道题运用了动规思想,要注意的是这道题多了一个位置的记录,所以起点额选择会更新,因此要定义一个变量去记录起点的位置,而且还要注意输出的格式。#include<iostream> #include<cstdio> using namespace std; int main() { int n; int a[100010]; scanf("%d",&n); int k=0,m,maxn,temp,position,begining,ending,i; while(n--) { k++; scanf("%d",&m); for(int i=0;i<m;i++) { scanf("%d",&a[i]); } maxn=temp=a[0]; position=begining=ending=0; for( i=1;i<m;i++) { if(temp+a[i]<a[i]) { temp=a[i]; position=i; } else { temp+=a[i]; } if(temp>maxn) { maxn=temp; begining=position; ending=i; } } printf("Case %d:\n%d %d %d\n",k,maxn,begining+1,ending+1); if(n) printf("\n"); } return 0; }