Submission #623404

#	Time	Username	Problem	Language	Result	Execution time	Memory
623404		Theo830	DEL13 (info1cup18_del13)	C++17	40 / 100	7 ms	4052 KiB

del13

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e9+7;
const ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<ii,ll>
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
ll dp[100005][3];
vll arr;
ll siz;
bool solve(ll idx,ll last){
    ll num = arr[idx] - last;
    if(num < 0){
        return false;
    }
    if(idx == siz-1){
        if(num % 2 == 0){
            if(last == 0 && arr[idx] != 0){
                return false;
            }
            return true;
        }
        return false;
    }
    if(dp[idx][last] != -1){
        return dp[idx][last];
    }
    bool ok = 0;
    if(num % 2 == 0){
        if(num >= 2){
            ok |= solve(idx + 1,2);
        }
        if(num == 0 || last != 0){
            ok |= solve(idx + 1,0);
        }
    }
    else{
        ok = solve(idx + 1,1);
    }
    return dp[idx][last] = ok;
}
int main(void){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    ll t;
    cin>>t;
    while(t--){
        ll n,r;
        cin>>n>>r;
        ll last = 0;
        arr.clear();
        f(i,0,r){
            ll a;
            cin>>a;
            arr.pb(a - last - 1);
            last = a;
        }
        arr.pb(n - last);
        siz = arr.size();
        f(i,0,siz+5){
            f(j,0,3){
                dp[i][j] = -1;
            }
        }
        f(i,0,siz){
            if(arr[i] > 4){
                if(arr[i] % 2 == 0){
                    arr[i] = 4;
                }
                else{
                    arr[i] = 3;
                }
            }
        }
        bool ok = solve(0,0);
        if(!ok){
            cout<<"-1\n";
        }
        else{
            cout<<"0\n";
            cout<<"\n";
        }
    }
}

Compilation message (stderr)

del13.cpp: In function 'bool solve(ll, ll)':
del13.cpp:57:26: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   57 |     return dp[idx][last] = ok;
      |            ~~~~~~~~~~~~~~^~~~

• Subtask 1: 6 / 15
• Subtask 2: 6 / 15
• Subtask 3: 6 / 15
• Subtask 4: 10 / 25
• Subtask 5: 12 / 30