Submission #697311

#	Time	Username	Problem	Language	Result	Execution time	Memory
697311		Dan4Life	The short shank; Redemption (BOI21_prison)	C++17	10 / 100	167 ms	25044 KiB

prison

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

#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define int long long 
#define sz(a) (int)a.size()
#define all(a) a.begin(),a.end()
const int mxN = (int)5e5+10;
const int LINF = (int)1e18;
int n, k, T, a[mxN];
int dp[mxN], dp2[mxN];
int segTree[mxN*4];

void upd(int i, int v, int p=1, int l=1,int r=n+1){
    if(l==r){ segTree[p]+=v; return; }
    int mid = (l+r)/2;
    if(i<=mid) upd(i,v,p*2,l,mid);
    else upd(i,v,p*2+1,mid+1,r);
    segTree[p]=max(segTree[p*2],segTree[p*2+1]);
}

int query(int i, int j, int p=1,int l=1,int r=n+1){
    if(i>r or j<l or i>j) return -1;
    if(i<=l and r<=j) return segTree[p];
    int mid=(l+r)/2;
    return max(query(i,j,p*2,l,mid),query(i,j,p*2+1,mid+1,r));
}

int32_t main() {
    ios_base::sync_with_stdio(false); cin.tie(0);
    cin >> n >> k >> T; k++;
    for(int i = 1; i <= n; i++) cin >> a[i];
    int ans = 0, mn = a[1];
    for(int j = 1; j <= n; j++)
        mn = min(mn+1, a[j]), ans+=(mn<=T), dp[j] = ans;
    dp2[n] = (a[n]<=T); upd(n+1,n+1);
    for(int i = n-1; i >= 1; i--){
        if(a[i]<=T){
            int r = min(n+1,i+T-a[i]+1);
            int c = min(n-i+1,T-a[i]+1);
            dp2[i]=query(i+1,r)-i;
        }
        else dp2[i]=dp2[i+1];
        upd(i,dp2[i]+i);
    }
    for(int i = 1; i < n; i++) ans = min(ans, dp[i]+dp2[i+1]);
    cout << ans;
}

Compilation message (stderr)

prison.cpp: In function 'int32_t main()':
prison.cpp:43:17: warning: unused variable 'c' [-Wunused-variable]
   43 |             int c = min(n-i+1,T-a[i]+1);
      |                 ^

• Subtask 1: 0 / 15
• Subtask 2: 10 / 10
• Subtask 3: 0 / 20
• Subtask 4: 0 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20