Submission #3982952

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<char> c(2 * n);
    vector<int> a(2 * n);
    vector<int> b(n), w(n);
    for (int i = 0; i < 2 * n; i++) {
        cin >> c[i] >> a[i];
        if (c[i] == 'B') b[a[i] - 1] = i;
        else w[a[i] - 1] = i;
    }

    vector<int> memo1(2 * n, 0);
    for (int i = 0; i < 2 * n; i++) {
        for (int j = 0; j < i; j++) {
            if (c[i] != c[j]) continue;
            memo1[i] += (a[i] < a[j]);
        }
    }

    vector< vector<int> > memo2(2 * n, vector<int>(n + 1, 0));
    for (int i = 0; i < 2 * n; i++) {
        for (int j = 0; j < i; j++) {
            if (c[i] == c[j]) continue;
            memo2[i][0]++;
            memo2[i][a[j]]--;
        }

        for (int j = 0; j < n; j++) {
            memo2[i][j + 1] += memo2[i][j];
        }
    }

    vector< vector<ll> > dp(n + 1, vector<ll>(n + 1, 1000000000000LL));
    dp[0][0] = 0;
    for (int i = 0; i <= n; i++) {
        for (int j = 0; j <= n; j++) {
            if (i < n) dp[i + 1][j] = min(dp[i + 1][j], dp[i][j] + memo1[w[i]] + memo2[w[i]][j]);
            if (j < n) dp[i][j + 1] = min(dp[i][j + 1], dp[i][j] + memo1[b[j]] + memo2[b[j]][i]);
        }
    }

    cout << dp[n][n] << endl;
    return 0;
}

Submission Info

Judge Result