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OI-codes/Luogu/P2964/P2964.cpp

44 lines
808 B
C++

#include <iostream>
using std::cin;
using std::cout;
const char endl = '\n';
const int N = 2005;
// f[当前位置][上一组长度]
int n, a[N], s[N], f[N][N];
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> a[i];
}
for (int i = n; i; i--) {
s[i] = s[i + 1] + a[i];
}
for (int i = n; i; i--) {
for (int j = 1, k = 1; j <= n; j++, k += 2) {
f[i][j] = f[i][j - 1];
if (k <= n - i + 1) {
f[i][j] = std::max(f[i][j], s[i] - f[i + k][k]);
}
if (k + 1 <= n - i + 1) {
f[i][j] = std::max(f[i][j], s[i] - f[i + k + 1][k + 1]);
}
}
}
cout << f[1][1] << endl;
return 0;
}