洛谷P3392 塗國旗進階解法

#include<iostream>

using namespace std;
char f[51][51];
int N, M, sum=10000;

int main()
{
	int temp = 0;
	cin >> N >> M;
	for (int i = 0; i < N; i++)
		for (int j = 0; j < M; j++)
			cin >> f[i][j];
	for (int i = 1; i < N - 1; i++)
		for (int s = i + 1; s <= N - 1; s++)
		{
			for (int j = 1; j < i; j++)
				for (int k = 0; k < M; k++)
					if ('W' != f[j][k])
						temp++;
			for (int j = i; j < s; j++)
				for (int k = 0; k < M; k++)
					if ('B' != f[j][k])
						temp++;
			for (int j = s; j < N - 1; j++)
				for (int k = 0; k < M; k++)
					if ('R' != f[j][k])
						temp++;
			if (temp < sum)
				sum = temp;
			temp = 0;
		}
	for (int i = 0; i < M; i++)
		if ('W' != f[0][i])
			sum++;
	for (int i = 0; i < M; i++)
		if ('R' != f[N - 1][i])
			sum++;
	cout << sum;
	return 0;
}