Codeforces Good Bye 2015 C. New Year and Domino (预处理)

C. New Year and Domino
time limit per test
3 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

They say "years are like dominoes, tumbling one after the other". But would a year fit into a grid? I don't think so.

Limak is a little polar bear who loves to play. He has recently got a rectangular grid withh rows andw columns. Each cell is a square, either empty (denoted by '.') or forbidden (denoted by '#'). Rows are numbered1 through h from top to bottom. Columns are numbered1 through w from left to right.

Also, Limak has a single domino. He wants to put it somewhere in a grid. A domino will occupy exactly two adjacent cells, located either in one row or in one column. Both adjacent cells must be empty and must be inside a grid.

Limak needs more fun and thus he is going to consider some queries. In each query he chooses some rectangle and wonders, how many way are there to put a single domino inside of the chosen rectangle?

Input

The first line of the input contains two integers h andw (1 ≤ h, w ≤ 500) – the number of rows and the number of columns, respectively.

The next h lines describe a grid. Each line contains a string of the lengthw. Each character is either '.' or '#' — denoting an empty or forbidden cell, respectively.

The next line contains a single integer q (1 ≤ q ≤ 100 000) — the number of queries.

Each of the next q lines contains four integersr1i,c1i,r2i,c2i (1 ≤ r1i ≤ r2i ≤ h, 1 ≤ c1i ≤ c2i ≤ w) — the i-th query. Numbers r1i and c1i denote the row and the column (respectively) of the upper left cell of the rectangle. Numbersr2i andc2i denote the row and the column (respectively) of the bottom right cell of the rectangle.

Output

Print q integers, i-th should be equal to the number of ways to put a single domino inside thei-th rectangle.

Sample test(s)
Input
5 8
....#..#
.#......
##.#....
##..#.##
........
4
1 1 2 3
4 1 4 1
1 2 4 5
2 5 5 8
Output
4
0
10
15
Input
7 39
.......................................
.###..###..#..###.....###..###..#..###.
...#..#.#..#..#.........#..#.#..#..#...
.###..#.#..#..###.....###..#.#..#..###.
.#....#.#..#....#.....#....#.#..#..#.#.
.###..###..#..###.....###..###..#..###.
.......................................
6
1 1 3 20
2 10 6 30
2 10 7 30
2 2 7 7
1 7 7 7
1 8 7 8
Output
53
89
120
23
0
2
Note

A red frame below corresponds to the first query of the first sample. A domino can be placed in 4 possible ways.



题意:给你一个地图,有的地方不能放东西,有的地方能放东西,然后给你一些区域的对角两端坐标,求能放多少个

长度为2的东西


思路:预处理行和列从头开始到当前位置能放的木棍数,如果上一位是空位,并且这一位置也是空位,就可以+1,然后按行按列查找相加


总结:写的时候有点糊涂,改了好多次才改好,对上样例交了,没想到A了


ac代码:

#include<stdio.h>
#include<math.h>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<iostream>
#include<algorithm>
#define MAXN 60001
#define LL long long
#define ll __int64
#define INF 0xfffffff
#define mem(x) memset(x,0,sizeof(x))
#define PI acos(-1)
using namespace std;
int num[550][550];
char map[550][550];
int a[550][550];
int b[550][550];
int main()
{
	int n,m,i,j,t,x1,x2,y1,y2;
	while(scanf("%d%d",&n,&m)!=EOF)
	{
		for(i=1;i<=n;i++)
		scanf("%s",map[i]+1);
		for(i=1;i<=n;i++)
		{
			for(j=1;j<=m;j++)
			{
				if(map[i][j]=='.')
				num[i][j]=0;
				else
				num[i][j]=1;
			}
		}
		mem(a);mem(b);
		for(i=1;i<=n;i++)//按行处理到达每个位置能放的木棍数
		{
			for(j=2;j<=m;j++)
			{
				if(num[i][j-1]==0&&num[i][j]==0)
				a[i][j]=a[i][j-1]+1;
				else
				a[i][j]=a[i][j-1];
			}
		}
		for(i=1;i<=m;i++)//按列处理到达每个位置能放的木棍数
		{
			for(j=2;j<=n;j++)
			{
				if(num[j-1][i]==0&&num[j][i]==0)
				b[j][i]=b[j-1][i]+1;
				else
				b[j][i]=b[j-1][i];
			}
		}
		scanf("%d",&t);
		while(t--)
		{
			scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
			ll ans=0;
//			for(i=1;i<=m;i++)
//			printf("%d ",a[1][i]);
			for(i=x1;i<=x2;i++)
			{
				ans+=a[i][y2]-a[i][y1];
				//printf("%d %d\n",a[i][y2],a[i][y1]);
			}
			//printf("%I64d\n",ans);
			for(i=y1;i<=y2;i++)
			{
				ans+=b[x2][i]-b[x1][i];
			}
			printf("%I64d\n",ans);
		}
	}
	return 0;
}



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