Submission #8315955

---

Source Code Expand

#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <string>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int mod = 1000000007;

int t[4004];

void inc(int x, int v) {
    for (; x <= 4000; x += x & -x) t[x] += v;
}

int que(int x) {
    int z = 0;
    for (; x; x -= x & -x) z += t[x];
    return z;
}

int main() {
    ios::sync_with_stdio(false);
    int n, a[4004] = {}, z = 0, u[2019] = {}, v[2019] = {}, d[2019][2019] = {};
    char c[4004] = {};
    cin >> n;
    for (int i = 1; i <= n + n; i++) cin >> c[i] >> a[i];
    for (int i = 1; i <= n + n; i++) {
        if (c[i] == 'W') u[a[i]] = i;
        else v[a[i]] = i;
    }
    for (int i = 0; i <= n; i++) {
        for (int j = 1; j <= n + n; j++) t[j] = 0;
        for (int j = 1; j <= n + n; j++) inc(j, 1);
        for (int j = 1; j <= i; j++) inc(u[j], -1), d[i][0] += que(u[j]);
        for (int j = 1; j <= n; j++) {
            inc(v[j], -1);
            d[i][j] = d[i][j - 1] + que(v[j]);
            if (i) d[i][j] = min(d[i][j], d[i - 1][j] + que(u[i]));
        }
    }
    cout << d[n][n];
}

Submission Info

Judge Result