Submission #996736

#	Time	Username	Problem	Language	Result	Execution time	Memory
996736		cot	JJOOII 2 (JOI20_ho_t2)	C++14	0 / 100	0 ms	344 KiB

ho_t2

#include <iostream>
#include <algorithm>
#include <vector>
#include <math.h>
#include <set>
#define int long long
#define ff first
#define ss second
#define pb push_back
#define pp pop_back
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define r0 return 0
using namespace std;
const int N = 3 * 1e5 + 5, M = 55, MOD = 998244353;
int n,m,k,l,r,q,cur,pos1,pos2,ans;
string s;
int pref1[N],pref2[N],pref3[N];
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    cin >> n >> k;
    cin >> s; s = " " + s;
    
    for (int i = 1; i <= n; i++) {
        pref1[i] = pref1[i - 1] + (s[i] == 'J');
        pref2[i] = pref2[i - 1] + (s[i] == 'O');
        pref3[i] = pref3[i - 1] + (s[i] == 'I');
    }
    ans = 1e9;
    for (int i = 1; i <= n; i++) {
        if (s[i] != 'J') continue;
        
        int l = 1,r = i;
        cur = 1e9;
        while (l <= r) {
            int mid = (l + r) / 2;
            if (pref1[i] - pref1[mid - 1] >= k) {
                cur = mid;
                l = mid + 1;
            } else {
                r = mid - 1;
            }
        }
        if (cur == 1e9) continue;
        
        pos1 = 1e9;
        l = i; r = n;
        while (l <= r) {
            int mid = (l + r) / 2;
            if (pref2[mid] - pref2[i - 1] >= k) {
                pos1 = mid;
                r = mid - 1;
            } else {
                l = mid + 1;
            }
        }
        if(pos1 == 1e9) continue;
        
        pos2 = 1e9;
        l = pos1; r = n;
        while (l <= r) {
            int mid = (l + r) / 2;
            if (pref3[mid] - pref3[r - 1] >= k) {
                pos2 = mid;
                r = mid - 1;
            } else {
                l = mid + 1;
            }
        }
        if (pos2 == 1e9) continue;
        ans = min(ans,pos2 - pos1 + 1 - 3 * k);
    }
    if (ans == 1e9) {
        cout << -1 << endl;
    } else {
        cout << ans << endl;
    }
}

• Subtask 1: 0 / 1
• Subtask 2: 0 / 12
• Subtask 3: 0 / 87