大概抄了 第一篇题解 的思路（（（

#include <bits/stdc++.h>
using namespace std;
int n, m;
stack<int> s[405];
bool b[405];
queue<pair<int, int>> q;
int count(stack<int> X, int y) {
	int cnt = 0;
	while(!X.empty()) {
		if(X.top() == y) cnt++;
		X.pop();
	}
	return cnt;
}
void work(int a, int b, int c, int y) {
	auto X = s[a], H = s[b], N = s[c];
	int A = count(X, y);
	for(int i = 0; i < A; i++) {
		q.push({b, c});
		N.push(H.top());
		H.pop();
	}
	while(!X.empty()) {
		if(X.top() == y) {
			q.push({a, b});
			H.push(X.top());
		} else {
			q.push({a, c});
			N.push(X.top());
		}
		X.pop();
	}
	for(int i = 0; i < m - A; i++) {
		q.push({c, a});
		X.push(N.top());
		N.pop();
	}
	for(int i = 0; i < A; i++) {
		q.push({b, a});
		X.push(H.top());
		H.pop();
	}
	while(!N.empty()) {
		q.push({c, b});
		H.push(N.top());
		N.pop();
	}
	s[a] = X, s[b] = H, s[c] = N;
}
int full(int y) {
	for(int i = 1; i <= n + 1; i++) 
		if(y != i && !b[i] && s[i].size() == m) 
			return i;
}
int empty() {
	for(int i = 1; i <= n + 1; i++) 
		if(!b[i] && s[i].empty()) 
			return i;
}
int have() {
	for(int i = 1; i <= n + 1; i++) 
		if(!b[i] && !s[i].empty()) 
			return i;
}
int main() {
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//	freopen("ball1.in", "r", stdin);
//	freopen("ball1.out", "w", stdout);
	cin>>n>>m;
	for(int i = 1; i <= n; i++)
		for(int j = 1; j <= m; j++) {
			int x;
			cin>>x;
			s[i].push(x);
		}
	for(int y = 1; y < n; y++) {
		int e = empty();
		for(int i = 1; i <= n; i++) 
			if(!b[i] && !s[i].empty() && i != e) {
				int f = full(i);
			//	cout<<"work(i"<<i<<",f"<<f<<",e"<<e<<",y"<<y<<")"<<endl;
				work(i, f, e, y);
				while(s[i].top() == y) {
					q.push({i, e});
					s[e].push(s[i].top());
					s[i].pop();
				}
			}
		int h = have(), i = 1;
		while(!s[h].empty() && i <= n + 1) {
			if(h == i) i++;
			while(s[i].size() < m && !s[h].empty()) {
				q.push({h, i});
				s[i].push(s[h].top());
				s[h].pop();
			}
			i++;
		}
		b[e] = 1;
	}
	cout<<q.size()<<endl;
	while(!q.empty()) {
		cout<<q.front().first<<" "<<q.front().second<<endl;
		q.pop();
	}
	return 0;
}