Solution

#include <bits/stdc++.h>
using namespace std;
 
int main(){
  int n;
  cin >> n;
  int arr[n];
  for(int i = 0; i < n; i++){
    cin >> arr[i];
  }
 
  long long int sum = 0;
  for(int i = 0; i < n; i++){
    sum += arr[i];
  }
 
  long long int ans = sum - n;
  cout << ans << "\n";
}

Solution

#include <bits/stdc++.h>
using namespace std;
 
int main(){
  int n;
  cin >> n;
  int v[n];
  for(int i = 0; i < n; i++) cin >> v[i];
 
  int prefix[n+1][30];
  for(int i = 0; i < 30; i++) prefix[0][i] = 0;
 
  for(int i = 0; i < n; i++){
    for(int j = 0; j < 30; j++){
      prefix[i+1][j] = prefix[i][j];
      prefix[i+1][j] += ((v[i] >> j) & 1); 
    }
  }
 
  int q;
  cin >> q;
  int ans[n] = {0};
  while(q--){
    int l, r;
    cin >> l >> r;
    int result = 0;
    for(int i = 0; i < 30; i++){
      if(prefix[r][i] - prefix[l-1][i] == r - l + 1){
        result |= (1 << i);
      }
    }
 
    ans[l-1] ^= result;
    if(r != n)
    ans[r] ^= result;
  }
 
  for(int i = 1; i < n; i++){
    ans[i] ^= ans[i-1];
  }
 
  for(int i = 0; i < n; i++){
      ans[i] ^= v[i];
    cout << ans[i] << " ";
  }
  cout << "\n";
 
}

Solution

#include <bits/stdc++.h>
using namespace std;

#define all(x) (x).begin(), (x).end()
typedef long long ll;

const ll mod = 1e9 + 7;
const ll inf = 1e18;
const ll N = 5e2 + 5;

ll rec(ll i, ll num, ll sz, ll n, ll k, string &s, vector<vector<ll>> &dp) {
    if (i == n) return num;
    if (dp[i][sz] != -1) return dp[i][sz];
    ll ans = 0;
    if (sz < k) ans = max(ans, rec(i + 1, num * 10 + s[i] - '0', sz + 1, n, k, s, dp));
    ans = max(ans, num + rec(i + 1, s[i] - '0', 1, n, k, s, dp));
    return dp[i][sz] = ans;
}

void solve() {
    ll n, k;
    string s;
    cin >> n >> k >> s;

    vector<vector<ll>> dp(n + 1, vector<ll>(k + 1, -1));

    cout << rec(0, 0, 0, n, k, s, dp) << '\n';
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll t = 1;
    // cin >> t;
    for (ll T = 1; T <= t; T++) {
        // cout << "case " << T << ": ";
        solve();
    }
    return 0;
}