刚学dp，为啥好多都TLE了

#include<bits/stdc++.h>

using namespace std;

const int N=1100;

int a[N][N], dp[N][N];

int n;

int dfs(int i,int j)

{

if(i==n)return a[i][j];

return

dp[i][j]=max(dfs(i+1,j),dfs(i+1,j+1))+

a[i][j];

}

int main()

{

cin>>n;

for(int i=1;i<=n;i++) { for(int j=1;j<=i;j++) {

cin>>a[i][j];

}

} cout<<dfs(1,1);

}