hdu 5480(维护前缀和+思路题) Conturbatio

Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 786 Accepted Submission(s): 358

Problem Description

There are many rook on a chessboard, a rook can attack the row and column it belongs, including its own place.

There are also many queries, each query gives a rectangle on the chess board, and asks whether every grid in the rectangle will be attacked by any rook?

Input

The first line of the input is a integer

Output

For every query output "Yes" or "No" as mentioned above.

Sample Input

Sample Output

Yes
No
Yes
Hint


Huge input, scanf recommended.

Source

BestCoder Round #57 (div.2)

题意:在一个棋盘上有一些"车"，他能够攻击到与它同一行或者同一列的棋盘上的所有的格子，现在给出K个棋子的坐标，然后有Q组询问，每一次询问(x1,y1,x2,y2)这个方格内的所有棋子是否能够全部被攻击到。

题解:维护前缀和,统计 (x1-x2) 这一段区间里面的被攻击到的行的数量，统计(y1-y2)这一段区间里面的被攻击到的列的数量,如果sum(x1~x2) == x2-x1+1 ，那么这段区间全部能够被攻击到,列也就不用考虑了，对列的考虑亦如此。

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <stack>
#include <vector>
#include <algorithm>
using namespace std;
const int N = 100005;
int flag_x[N],flag_y[N];
int main()
{
    int tcase;
    scanf("%d",&tcase);
    while(tcase--){
        int n,m,k,q;
        scanf("%d%d%d%d",&n,&m,&k,&q);
        memset(flag_x,0,sizeof(flag_x));
        memset(flag_y,0,sizeof(flag_y));
        int x,y;
        for(int i=1;i<=k;i++){
            scanf("%d%d",&x,&y);
            flag_x[x] = 1;
            flag_y[y] = 1;
        }
        for(int i=1;i<=n;i++){
            flag_x[i]+= flag_x[i-1];
        }
        for(int i=1;i<=m;i++){
            flag_y[i] += flag_y[i-1];
        }
        while(q--){
            int x1,y1,x2,y2;
            scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
            if(flag_x[x2]-flag_x[x1-1]==x2-x1+1||flag_y[y2]-flag_y[y1-1]==y2-y1+1) printf("Yes
");
            else printf("No
");
        }
    }
    return 0;
}

hdu 5480(维护前缀和+思路题) Conturbatio

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