分治 + 推式子（构造绝对值不等式）  
交换行的元素时每列的元素个数不变，交换列时同理，所以可以分别考虑行和列
对于行（列），可以看成均分纸牌的模型，唯一的不同点是从链变成了环（首尾可交换）
然后就可以推式子了

推式子具体过程

#include<bits/stdc++.h>
using namespace std;

#define fr first
#define se second
#define et0 exit(0);

typedef long long LL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef unsigned long long ULL;

const int INF = 0X3f3f3f3f, N = 1e5 + 10, MOD = 1e9 + 7;

int row[N], clm[N];
LL c[N];

LL calc(int n, int a[], int sum) {
	if (sum % n) return -1;
	int ave = sum / n;
	for (int i = 1; i <= n; i++) a[i] -= ave;

	c[1] = 0;
	for (int i = 2; i <= n; i++) c[i] = c[i - 1] + a[i];
	sort(c + 1, c + n + 1);

	LL res = 0;
	int mid = n / 2 + 1;
	for (int i = 1; i <= n; i++) res += abs(c[mid] - c[i]);

	return res;
}

void work() {
	int n, m, t;
	cin >> n >> m >> t;
	for (int i = 1; i <= t; i++) {
		int x, y;
		cin >> x >> y;
		row[x]++;
		clm[y]++;
	}
	LL ct1 = calc(n, row, t), ct2 = calc(m, clm, t);
	if (ct1 == -1 && ct2 == -1) cout << "impossible" << endl;
	else if (ct2 == -1) cout << "row " << ct1 << endl;
	else if (ct1 == -1) cout << "column " << ct2 << endl;
	else cout << "both " << ct1 + ct2 << endl;
}

signed main() {

	work();

	return 0;
}

标签：clm,typedef,row,int,LL,long,105,七夕,AcWing
来源： https://www.cnblogs.com/xhy666/p/16435210.html