10703 - Free spots, uva

#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<vector>
#define db(a) cout << #a << " = " << a << endl;
int board[500][500];
using namespace std;
int main(){
	int W, H, N, X1, Y1, X2, Y2, total;
	while(scanf("%d%d%d", &W, &H, &N)){
		if(W == 0 && H == 0 && N == 0) break;
		total = W * H;
		for(int i = 0; i < H; i++)
				for(int j = 0; j < W; j++)
					board[i][j] = 1;
		for(int k = 0; k < N; k++){
			scanf("%d%d%d%d", &X1, &Y1, &X2, &Y2);
			X1--, Y1--, X2--, Y2--;
			if(X1 > X2) swap(X1, X2);
			if(Y1 > Y2) swap(Y1, Y2);
			for(int i = Y1; i <= Y2; i++)
				for(int j = X1; j <= X2; j++)
					if(board[i][j]) board[i][j] = 0, total--;
		}
		if(total) 
			if(total != 1) 
				printf("There are %d empty spots.\n", total);
			else 
				printf("There is one empty spot.\n");
		else
			printf("There is no empty spots.\n");
	}
	return 0;
}