C++

$\color{#cc33ff}{— > 算法基础课题解}$

$分析：$

#include<iostream>
#include<algorithm>

using namespace std;

const int N = 510, INF = 1e9;

int n;
int a[N][N];
int f[N][N];

int main() {
    cin >> n;
    for (int i = 1; i <= n; i ++)
        for (int j = 1; j <= i; j ++)
            cin >> a[i][j];

    for (int i = 0; i <= n; i ++) // 初始化
        for (int j = 0; j <= i + 1; j ++)
            f[i][j] = -INF;

    f[1][1] = a[1][1];
    for (int i = 2; i <= n; i ++)
        for (int j = 1; j <= i; j ++)
            f[i][j] = max(f[i - 1][j - 1] + a[i][j], f[i - 1][j] + a[i][j]);

    int res = -INF;
    for (int i = 1; i <= n; i ++) res = max(res, f[n][i]); // 在最底层找最大的一个

    cout << res;
    return 0;
}