#include <iostream>
#include <algorithm>
#include <deque>
using namespace std;
int pop[3007];
int nast[3007];
int scale[3007];
bool vis[3007];
int n;
void swap_elems(int a, int b, deque<int>& move) {
move.push_front(a + 1);
move.push_back(b + 1);
swap(pop[a], pop[b]);
nast[pop[a]] = a;
nast[pop[b]] = b;
// cout << "swap " << a << " " << b << "\n";
// for (int i = 0; i < n; i++) {
// cout << pop[i] << " ";
// }
// cout << "\n";
// for (int i = 0; i < n; i++) {
// cout << nast[i] << " ";
// }
// cout << "\n";
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n;
for (int i = 0; i < n; i++) {
cin>>pop[i];
scale[i] = pop[i];
}
sort(scale, scale + n);
for (int i = 0; i < n; i++) {
pop[i] = (int)(lower_bound(scale, scale + n, pop[i]) - scale);
// cout << pop[i] + 1 << " ";
nast[pop[i]] = i;
}
// cout << "\n";
deque<int> first;
deque<int> second;
for (int i = 0; i < n; i++) {
if (vis[i] == 0) {
int v = i;
int len = 0;
while (vis[v] == false) {
vis[v] = true;
len++;
v = nast[v];
}
if (len == 1) {
// OK
}
else if (len == 2) {
swap_elems(i, nast[i], first);
}
else {
int a = i;
int b = nast[nast[i]];
swap_elems(a, b, first);
while (true) {
a = pop[b];
b = nast[b];
if (a == b) break;
swap_elems(a, b, first);
}
}
}
}
for (int i = 0; i < n; i++) vis[i] = false;
for (int i = 0; i < n; i++) {
if (vis[i] == 0) {
int v = i;
int len = 0;
while (vis[v] == false) {
vis[v] = true;
len++;
v = nast[v];
}
if (len == 1) {
// OK
}
else if (len == 2) {
swap_elems(i, nast[i], second);
}
else {
int a = i;
int b = nast[nast[i]];
swap_elems(a, b, second);
while (true) {
a = pop[b];
b = nast[b];
if (a == b) break;
swap_elems(a, b, second);
}
}
}
}
if (first.empty()) {
cout << 0 << "\n";
}
else if (second.empty()) {
cout << 1 << "\n";
cout << first.size() << "\n";
while (!first.empty()) {
cout << first.front() << " ";
first.pop_front();
}
}
else {
cout << 2 << "\n";
cout << first.size() << "\n";
while (!first.empty()) {
cout << first.front() << " ";
first.pop_front();
}
cout << "\n";
cout << second.size() << "\n";
while (!second.empty()) {
cout << second.front() << " ";
second.pop_front();
}
}
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 | #include <iostream> #include <algorithm> #include <deque> using namespace std; int pop[3007]; int nast[3007]; int scale[3007]; bool vis[3007]; int n; void swap_elems(int a, int b, deque<int>& move) { move.push_front(a + 1); move.push_back(b + 1); swap(pop[a], pop[b]); nast[pop[a]] = a; nast[pop[b]] = b; // cout << "swap " << a << " " << b << "\n"; // for (int i = 0; i < n; i++) { // cout << pop[i] << " "; // } // cout << "\n"; // for (int i = 0; i < n; i++) { // cout << nast[i] << " "; // } // cout << "\n"; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); cin>>n; for (int i = 0; i < n; i++) { cin>>pop[i]; scale[i] = pop[i]; } sort(scale, scale + n); for (int i = 0; i < n; i++) { pop[i] = (int)(lower_bound(scale, scale + n, pop[i]) - scale); // cout << pop[i] + 1 << " "; nast[pop[i]] = i; } // cout << "\n"; deque<int> first; deque<int> second; for (int i = 0; i < n; i++) { if (vis[i] == 0) { int v = i; int len = 0; while (vis[v] == false) { vis[v] = true; len++; v = nast[v]; } if (len == 1) { // OK } else if (len == 2) { swap_elems(i, nast[i], first); } else { int a = i; int b = nast[nast[i]]; swap_elems(a, b, first); while (true) { a = pop[b]; b = nast[b]; if (a == b) break; swap_elems(a, b, first); } } } } for (int i = 0; i < n; i++) vis[i] = false; for (int i = 0; i < n; i++) { if (vis[i] == 0) { int v = i; int len = 0; while (vis[v] == false) { vis[v] = true; len++; v = nast[v]; } if (len == 1) { // OK } else if (len == 2) { swap_elems(i, nast[i], second); } else { int a = i; int b = nast[nast[i]]; swap_elems(a, b, second); while (true) { a = pop[b]; b = nast[b]; if (a == b) break; swap_elems(a, b, second); } } } } if (first.empty()) { cout << 0 << "\n"; } else if (second.empty()) { cout << 1 << "\n"; cout << first.size() << "\n"; while (!first.empty()) { cout << first.front() << " "; first.pop_front(); } } else { cout << 2 << "\n"; cout << first.size() << "\n"; while (!first.empty()) { cout << first.front() << " "; first.pop_front(); } cout << "\n"; cout << second.size() << "\n"; while (!second.empty()) { cout << second.front() << " "; second.pop_front(); } } } |
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