#include<iostream>
#include<vector>
#include<limits.h>
#include<algorithm>
using namespace std;
//优化解法,O(N^3)
int maxSum(vector< vector<int> > &arr){
if (arr.empty()){
return 0;
}
int MAX = INT_MIN; //记录全局最大值
int cur = 0;
for (int i = 0; i < arr.size(); i++){//二维数组名表示行向量
vector<int> s(arr[0].size());
//二维数组列向量的大小,每次都需要重新申请,否则会造成全局变量无法更新,
//决策失败
for (int j = i; j < arr.size(); j++){
//[i.....j]列的范围
cur = 0;
for (int k = 0; k < s.size(); k++){
//有几行进行决策
s[k] += arr[j][k];
cur += s[k];
MAX = max(MAX, cur);
cur = cur < 0 ? 0 : cur;
//cout << cur << endl;
}
}
}
return MAX;
}
int main(){
vector< vector<int> > vec(2, vector<int>(4));
int arr[] = { 3, 2, 1, 4, -6, 5, 2, -7 };
int t = 0;
for (int i = 0; i < 2; i++){
for (int j = 0; j < 4; j++){
vec[i][j] = arr[t++];
//cout << vec[i][j] << endl;
}
}
int res = maxSum(vec);
cout << res << endl;
return 0;
}