1007. Maximum Subsequence Sum (25) 第二种想法

1007. Maximum Subsequence Sum (25)

时间限制400 ms内存限制65536 kB代码长度限制16000 B判题程序Standard作者CHEN, YueGiven a sequence of K integers { N1, N2, ..., NK }. A continuous subsequence is defined to be { Ni, Ni+1,..., Nj } where 1 <= i <= j <= 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 (<= 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 subsequenceis 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

额 第二种想法算法复杂度大概是n³ 然后超时了 还有个答案运算错误了

#include<iostream>using namespace std;int n[10012];int main(){int k;cin>>k;bool flag=false;for(int i=0;i<k;i++){cin>>n[i];if(n[i]>=0) flag=1;}if(!flag) cout<<"0 "<<n[1]<<" "<<n[k]<<endl;else{int max=0,a=0,b=0;for(int j=k;j;j--){int x=k-j;for( int h=0;h<=x;h++){int sum=0;for(int i=0;i<j;i++){sum+=n[i+h];if(sum>max) {max=sum;        a=n[h];        b=n[i+h];} }}}cout<<max<<" "<<a<<" "<<b<<endl;}return 0;}