poj-1195-Mobile Phones

/// poj -1195 
#include <cstdio> 
#include <cstring> 
const int MAXN = 1025; 

int s, mp[MAXN][MAXN]; 

inline int lowbit(int x){
	return x & (-x); 
}

long long Compute(int x1, int y1, int x2, int y2){
	long long  ans, ans1 = 0, ans2 = 0, ans3 = 0, ans4 = 0; 
	for(int i=x1-1; i>0; i-=lowbit(i)){
		for(int j=y1-1; j>0; j-=lowbit(j)){
			ans1 += mp[i][j]; 
		}
	}
	for(int i=x2; i>0; i-=lowbit(i)){
		for(int j=y2; j>0; j-=lowbit(j)){
			ans2 += mp[i][j]; 
		}
	}
	for(int i=x2; i>0; i-=lowbit(i)){
		for(int j=y1-1; j>0; j-=lowbit(j)){
			ans3 += mp[i][j]; 
		}
	}
	for(int i=x1-1; i>0; i-=lowbit(i)){
		for(int j=y2; j>0; j-=lowbit(j)){
			ans4 += mp[i][j]; 
		}
	}
	ans = ans1 + ans2 - ans4 - ans3; 
	return ans; 
}

void Add(int x, int y, const int val){
	for(int i=x; i<=s; i+=lowbit(i)){
		for(int j=y; j<=s; j+=lowbit(j)){
			mp[i][j] += val; 
		}
	}
}

int main(){
	freopen("in.txt", "r", stdin); 

	int n, x1, y1, x2, y2, val; 
	long long ans; 
	while(scanf("%d", &n ) != EOF){
		if(n >= 3){
			break; 
		}else if(n == 0){
			scanf("%d", &s); 
			memset(mp, 0, sizeof(mp)); 
		}else if(n == 1){
			scanf("%d %d %d", &x1, &y1, &val); 
			Add(x1 + 1, y1 + 1, val);  
		}else{
			scanf("%d %d %d %d", &x1,  &y1, &x2, &y2 ); 
			ans = Compute( x1 + 1, y1 + 1, x2 + 1, y2 + 1 ); 
			printf("%lld\n", ans );
		}
	} 
	return 0; 
}