Submission #212523

#	Time	Username	Problem	Language	Result	Execution time	Memory
212523		DystoriaX	JJOOII 2 (JOI20_ho_t2)	C++14	100 / 100	18 ms	2676 KiB

ho_t2

#include <bits/stdc++.h>

using namespace std;

int n, k;
char s[200010];
vector<int> J, O, I;
int lf[200010];
int ans = 1e9;

int main(){
    scanf("%d%d", &n, &k);
    scanf(" %s", s + 1);

    for(int i = 1; i <= n; i++){
        if(s[i] == 'J') J.emplace_back(i);
        if(s[i] == 'O') O.emplace_back(i);
        if(s[i] == 'I') I.emplace_back(i);
    }

    for(int i = k - 1; i < (int) J.size(); i++){
        lf[J[i]] = J[i - k + 1];
    }

    for(int i = k - 1; i < (int) O.size(); i++){
        auto it = upper_bound(J.begin(), J.end(), O[i - k + 1]);

        if(it == J.begin()) continue;
        --it;

        if(lf[*it] == 0) continue;
        lf[O[i]] = lf[*it];
    }

    for(int i = k - 1; i < (int) I.size(); i++){
        auto it = upper_bound(O.begin(), O.end(), I[i - k + 1]);
    
        if(it == O.begin()) continue;
        --it;

        if(lf[*it] == 0) continue;

        ans = min(ans, I[i] - lf[*it] + 1 - 3 * k);
    }

    if(ans == 1e9) ans = -1;

    printf("%d\n", ans);
    
    return 0;
}

Compilation message (stderr)

ho_t2.cpp: In function 'int main()':
ho_t2.cpp:12:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &k);
     ~~~~~^~~~~~~~~~~~~~~~
ho_t2.cpp:13:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf(" %s", s + 1);
     ~~~~~^~~~~~~~~~~~~~

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