Submission #885169

#	Time	Username	Problem	Language	Result	Execution time	Memory
885169		votranngocvy	Difference (POI11_roz)	C++14	60 / 100	1097 ms	18084 KiB

roz

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

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;
    for (int i = 1; i <= n; i++) val[i] = 0;
    for (auto x: pos[a]) val[x] = 1;
    for (auto x: pos[b]) val[x] = -1;
    maxPreSum[0] = maxSufSum[n + 1] = 0;
    int sum = 0;
    for (int i = 1; i <= n; i++) {
        sum = max(sum + val[i],val[i]);
        maxPreSum[i] = sum;
    }
    sum = 0;
    for (int i = n; i > 0; i--) {
        sum = max(sum + val[i],val[i]);
        maxSufSum[i] = sum;
    }
    int ans = 0;
    for (auto i: pos[b]) {
        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);
    }
    for (auto x: pos[b]) val[x] = 1;
    for (auto x: pos[a]) val[x] = -1;
    maxPreSum[0] = maxSufSum[n + 1] = 0;
    sum = 0;
    for (int i = 1; i <= n; i++) {
        sum = max(sum + val[i],val[i]);
        maxPreSum[i] = sum;
    }
    sum = 0;
    for (int i = n; i > 0; i--) {
        sum = max(sum + val[i],val[i]);
        maxSufSum[i] = sum;
    }
    for (auto i: pos[a]) {
        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 = i + 1; 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