数字三角形

传送门：https://www.luogu.org/problemnew/show/P1216

记忆化搜索，不然会T

#include<cstdio>
#include<algorithm> 
using namespace std;
int n,a[1005][1005],ans,f[1005][1005];
int dfs(int x,int y)
{
    if(f[x][y] == -1)
    {
        if(x == n) f[x][y] = a[x][y];
        else f[x][y] = a[x][y] + max(dfs(x+1,y),dfs(x+1,y+1));
    }
    return f[x][y];
}
int main()
{
    scanf("%d",&n);
    for(int i = 1;i <= n;i++)
        for(int j = 1;j <= i;j++)
        {
            scanf("%d",&a[i][j]);
            f[i][j] = -1;
        }
    dfs(1,1);
    printf("%d",f[1][1]);
    return 0;
}