Submission #599225

#	Time	Username	Problem	Language	Result	Execution time	Memory
599225		Temmie	Sorting (IOI15_sorting)	C++17	20 / 100	4 ms	3512 KiB

sorting

#include <bits/stdc++.h>

int findSwapPairs(int n, int a[], int m, int u[], int v[], int uu[], int vv[]) {
	int l = 0, r = m, best = m;
	int inv[200'005];
	int u1[200'005];
	int v1[200'005];
	int b[200'005];
	while (l <= r) {
		int mid = (l + r) >> 1;
		for (int i = 0; i < n; i++) {
			b[i] = a[i];
		}
		for (int i = 0; i < mid; i++) {
			std::swap(a[u[i]], a[v[i]]);
		}
		for (int i = 0; i < n; i++) {
			inv[a[i]] = i;
		}
		int need = 0;
		memset(u1, 0, sizeof(u1));
		memset(v1, 0, sizeof(v1));
		for (int i = 0; i < n; i++) {
			if (a[i] == i) {
				continue;
			}
			int node = i;
			while (a[node] != node) {
				std::swap(a[node], a[inv[node]]);
				u1[need] = node;
				v1[need] = inv[node];
				need++;
				node = inv[node];
				int x = node;
				int y = inv[node];
				inv[a[x]] = x;
				inv[a[y]] = y;
			}
		}
		if (need <= mid) {
			for (int i = 0; i < mid; i++) {
				uu[i] = u1[i];
				vv[i] = v1[i];
			}
			best = mid;
			r = mid - 1;
		} else {
			l = mid + 1;
		}
		for (int i = 0; i < n; i++) {
			a[i] = b[i];
		}
	}
	return best;
}

• Subtask 1: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 0 / 16
• Subtask 4: 0 / 18
• Subtask 5: 0 / 20
• Subtask 6: 0 / 26