HDU1003 简单DP

Max Sum

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

#include <bits/stdc++.h>
using namespace std;
const int MAXN =  + ;
int T, n;
int arr[MAXN], dp[MAXN];
int S, E;
int main() {
      scanf("%d", &T);
      for(int t = ; t < T; ++t) {
            S = E = ;
            cin >> n;
            for(int i = ; i != n; ++i)
                  cin >> arr[i];
            dp[] = arr[];
            for(int i = ; i != n; ++i)
                  if(dp[i-] >= )
                        dp[i] = dp[i-] + arr[i];
                  else
                        dp[i] = arr[i];
            int Max = dp[];
            for(int i = ; i != n; ++i)
                  if(dp[i] >= Max) {
                        Max = dp[i];
                        E = i;
                  }
            int sum = ;
            for(int i = E; i >= ; --i) {
                  sum += arr[i];
                  if(sum == Max)
                        S = i;
            }
            cout << "Case " << t+ << ":" << endl;
            cout << Max << " " << S+ << " " << E+ << endl;
            if(t < T-) puts("");
      }
      return ;
}

用了数组

#include <bits/stdc++.h>
using namespace std;

int main() {
      int T,n;
      int Max, S, E, sum, a;
      cin >> T;
      for(int t = ; t <= T; ++t) {
            cin >> n;
            S = E = sum = ;
            Max = -;
            int k = ;
            for(int i = ; i != n; ++i) {
                  cin >> a;
                  sum += a;
                  if(sum > Max) {
                        Max = sum;
                        S = k;
                        E = i;
                  }
                  if(sum < ) {
                        sum = ;
                        k = i + ;
                  }
            }
            cout << "Case " << t << ":" << endl;
            cout << Max << " " << S+ << " " << E+ << endl;
            if(t < T) puts("");
      }
      return ;
}

不用数组