算法1 from bottom to top

(DP)

时间复杂度

O($n^2$)

C++ 代码

#include<iostream>
using namespace std;

const int N = 510;
int f[N][N];

int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; ++i)
        for(int j = 1; j <= i; ++j)
            cin >> f[i][j];
    for (int i = N - 1; i >= 1; i--) {
        for (int j = 1; j <= i; ++j) {
            f[i][j] += max(f[i+1][j], f[i+1][j+1]);
        }
    }
    cout << f[1][1] << endl;
    return 0;
}