I am getting a runtime error in some test cases when I try to submit my code. Problem Link: https://atcoder.jp/contests/dp/tasks/dp_a

My code:

#include<bits/stdc  .h>
using namespace std;
#define int long long
 
int minCost(int n, vector<int> h, vector<int> dp) {
 
    if (dp[n] != -1) {
        return dp[n];
    }
    if (n == 1) {
        return dp[n] = 0;
    }
    if (n == 2) {
        return dp[n] = abs(h[1] - h[2]);
    }
 
    int oneStep = minCost(n - 1, h, dp)   abs(h[n] - h[n - 1]);
    int twoStep = minCost(n - 2, h, dp)   abs(h[n] - h[n - 2]);
 
    if (oneStep < twoStep) {
        return dp[n] = oneStep;
    }
    return dp[n] = twoStep;
}
 
int32_t main() {
 
    int n;
    cin >> n;
    vector<int> h(n   1);
    for (int i = 1; i <= n; i  ) {
        cin >> h[i];
    }
    vector<int> dp(n   1, -1);
    cout << minCost(n, h, dp);
 
    return 0;
}

i cannot figure out why it is giving runtime error. it works perfectly fine for sample tests.

CodePudding user response：

I'm not sure this is the only problem, in minCost() but you're passing dp by value, not reference. That means the compiler will make a copy of dp, not the actual dp.

Change your code to:

int minCost(int n, vector<int> h, vector<int>& dp)