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P5149 会议座位

R57929822
This commit is contained in:
Baoshuo Ren 2021-09-12 21:34:12 +08:00 committed by Baoshuo Ren
parent 86b2891eb0
commit 196af6aeb0
Signed by: baoshuo
GPG Key ID: 70F90A673FB1AB68

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#include <bits/stdc++.h>
using namespace std;
int n, a[100005], t[100005];
long long ans;
string s;
map<string, int> m1;
void merge_sort(int l, int r) {
if (l >= r) return;
int mid = l + r >> 1;
merge_sort(l, mid);
merge_sort(mid + 1, r);
int i = l, j = mid + 1, k = 0;
while (i <= mid && j <= r) {
if (a[i] <= a[j]) {
t[k++] = a[i++];
} else {
t[k++] = a[j++];
ans += (mid - i + 1);
}
}
while (i <= mid) {
t[k++] = a[i++];
}
while (j <= r) {
t[k++] = a[j++];
}
for (int i = l, j = 0; i <= r; i++, j++) {
a[i] = t[j];
}
}
int main() {
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> s;
m1[s] = i;
}
for (int i = 1; i <= n; i++) {
cin >> s;
a[i] = m1[s];
}
merge_sort(1, n);
cout << ans << endl;
return 0;
}