Submission #885539

#	Time	Username	Problem	Language	Result	Execution time	Memory
885539		votranngocvy	Difference (POI11_roz)	C++14	60 / 100	1056 ms	13288 KiB

roz

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

#define pii pair<int,int>
#define fi first
#define se second
#define mp make_pair
const int N = 1e6 + 5;
char a[N];
vector<int>pos[30];
int n,val[N],maxPreSum[N],maxSufSum[N];

int calc(int a,int b) {
    if (pos[a].size() == 0 || pos[b].size() == 0) return 0;
    vector<pii>vec;
    for (auto x: pos[a]) vec.push_back(mp(x,1));
    for (auto x: pos[b]) vec.push_back(mp(x,-1));
    int m = vec.size();
    sort(vec.begin(),vec.end());
    maxPreSum[0] = maxSufSum[m + 1] = 0;
    int sum = 0;
    for (int i = 1; i <= m; i++) {
        sum = max(sum + vec[i - 1].se,vec[i - 1].se);
        maxPreSum[i] = sum;
    }
    sum = 0;
    for (int i = m; i > 0; i--) {
        sum = max(sum + vec[i - 1].se,vec[i - 1].se);
        maxSufSum[i] = sum;
    }
    int ans = 0;
    for (int i = 1; i <= m; i++) {
        if (vec[i - 1].se == 1) continue;
        int tmp = maxPreSum[i - 1] + maxSufSum[i + 1] - 1;
        tmp = max(tmp,maxPreSum[i - 1] - 1);
        tmp = max(tmp,maxSufSum[i - 1] - 1);
        ans = max(ans,tmp);
    }
    return ans;
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= n; i++) pos[a[i] - 'a'].push_back(i);
    int ans = 0;
    for (int i = 0; i < 26; i++)
        for (int j = 0; j < 26; j++) 
            if (i != j) ans = max(ans,calc(i,j));
    cout << ans << "\n";
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10