Submission #1086824

#	Time	Username	Problem	Language	Result	Execution time	Memory
1086824		Icelast	JJOOII 2 (JOI20_ho_t2)	C++17	100 / 100	13 ms	6464 KiB

ho_t2

#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2*1e5+5, INF = 1e8+9;
void solve(){
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    s = ' ' + s;
    vector<int> J(n+2, 0), O(n+2, n+1), I(n+2, n+1);
    for(int i = n; i >= 1; i--){
        if(s[i] == 'O'){
            O[i] = i;
        }else{
            O[i] = O[i+1];
        }
    }
    for(int i = 1; i <= n; i++){
        if(s[i] == 'O'){
            O[i] = O[i+1];
        }
    }
    int j = -1, cnt = 0;
    for(int i = 1; i <= n; i++){
        if(s[i] == 'O'){
            cnt++;
            if(cnt == k){
                j = i;
                break;
            }
        }
    }
    if(j == -1){
        cout << -1;
        return;
    }
    vector<int> pfO(n+2, INF), OO(n+2, n+1);
    for(int i = 1; i <= n; i++){
        if(s[i] == 'O'){
            pfO[i] = j-i+1 - k;
            OO[i] = j;
            j = O[j];
        }

        if(j == n+1) break;
    }

    for(int i = n; i >= 1; i--){
        if(s[i] == 'I'){
            I[i] = i;
        }else{
            I[i] = I[i+1];
        }
    }
    for(int i = 1; i <= n; i++){
        if(s[i] == 'I'){
            I[i] = I[i+1];
        }
    }
    cnt = 0;
    j = -1;
    for(int i = 1; i <= n; i++){
        if(s[i] == 'I'){
            cnt++;
            if(cnt == k){
                j = i;
                break;
            }
        }
    }
    if(j == -1){
        cout << -1;
        return;
    }
    vector<int> pfI(n+2, INF);
    for(int i = 1; i <= n; i++){
        if(s[i] == 'I'){
            pfI[i] = j-i+1 - k;
            j = I[j];
        }
        if(j == n+1) break;
    }

    for(int i = 1; i <= n; i++){
        if(s[i] == 'J'){
            J[i] = i;
        }else{
            J[i] = J[i-1];
        }
    }
    for(int i = n; i >= 1; i--){
        if(s[i] == 'J'){
            J[i] = J[i-1];
        }
    }
    cnt = 0;
    j = -1;
    for(int i = n; i >= 1; i--){
        if(s[i] == 'J'){
            cnt++;
            if(cnt == k){
                j = i;
                break;
            }
        }
    }
    if(j == -1){
        cout << -1;
        return;
    }
    vector<int> pfJ(n+2, INF);
    for(int i = n; i >= 1; i--){
        if(s[i] == 'J'){
            pfJ[i] = i-j+1 - k;
            j = J[j];
        }
        if(j == 0) break;
    }
    int ans = INF;
    for(int i = 1; i <= n; i++){
        if(s[i] == 'O'){
            if(pfO[i] == INF) continue;
            ans = min(ans, pfJ[J[i]]+(i-J[i]-1) + pfO[i] + pfI[I[OO[i]]]+(I[OO[i]]-OO[i]-1));
            //cout << i << " " << pfJ[J[i]]+(i-J[i]-1) << " " << pfO[i] << " " << pfI[I[OO[i]]]+(I[OO[i]]-i-1)<< "s\n" ;
        }
    }
    if(ans == INF) ans = -1;
    cout << ans;
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    solve();
}

• Subtask 1: 1 / 1
• Subtask 2: 12 / 12
• Subtask 3: 87 / 87