• 二维前缀和


    一维前缀和 :

      这个优化 , 可以在 O (1) 的时间内计算出一个序列的和 ,

    二维前缀和 :

      对于一个矩阵 , 也可以在 O (1) 的时间内计算出矩阵 (x1~x2)( y1 ~ y2 ) 的和 。

      sum[ i ] [ j ] 表示矩阵 1 ~ i , 1 ~ j 的和 , 那么由容斥原理知 sum[ 0 ] [ j ] 和 sum [ i ] [ 0 ] 均为 0 。

      则  s[ x1 ~ x2 ] [ y1 ~ y2 ] = sum[ x2 , y2 ] + sum [ x1 - 1 ] [ y1 - 1 ] - sum [ x1 - 1 ][ y2 ] - sum [ x2 ] [ y1-1 ] 。

    The Cartesian coordinate system is set in the sky. There you can see n stars, the i-th has coordinates (xi, yi), a maximum brightness c, equal for all stars, and an initial brightness si (0 ≤ si ≤ c).

    Over time the stars twinkle. At moment 0 the i-th star has brightness si. Let at moment t some star has brightness x. Then at moment (t + 1) this star will have brightness x + 1, if x + 1 ≤ c, and 0, otherwise.

    You want to look at the sky q times. In the i-th time you will look at the moment ti and you will see a rectangle with sides parallel to the coordinate axes, the lower left corner has coordinates (x1i, y1i) and the upper right — (x2i, y2i). For each view, you want to know the total brightness of the stars lying in the viewed rectangle.

    A star lies in a rectangle if it lies on its border or lies strictly inside it.

    Input

    The first line contains three integers n, q, c (1 ≤ n, q ≤ 105, 1 ≤ c ≤ 10) — the number of the stars, the number of the views and the maximum brightness of the stars.

    The next n lines contain the stars description. The i-th from these lines contains three integers xi, yi, si (1 ≤ xi, yi ≤ 100, 0 ≤ si ≤ c ≤ 10) — the coordinates of i-th star and its initial brightness.

    The next q lines contain the views description. The i-th from these lines contains five integers ti, x1i, y1i, x2i, y2i (0 ≤ ti ≤ 109, 1 ≤ x1i < x2i ≤ 100, 1 ≤ y1i < y2i ≤ 100) — the moment of the i-th view and the coordinates of the viewed rectangle.

    Output

    For each view print the total brightness of the viewed stars.

    Example
    Input
    2 3 3
    1 1 1
    3 2 0
    2 1 1 2 2
    0 2 1 4 5
    5 1 1 5 5
    Output
    3
    0
    3
    Input
    3 4 5
    1 1 2
    2 3 0
    3 3 1
    0 1 1 100 100
    1 2 2 4 4
    2 2 1 4 7
    1 50 50 51 51
    Output
    3
    3
    5
    0
    Note

    Let's consider the first example.

    At the first view, you can see only the first star. At moment 2 its brightness is 3, so the answer is 3.

    At the second view, you can see only the second star. At moment 0 its brightness is 0, so the answer is 0.

    At the third view, you can see both stars. At moment 5 brightness of the first is 2, and brightness of the second is 1, so the answer is 3.

    如果这题是遍历 所有的点 , 那么一定会超时 , 由于灯亮度变化范围较小 , 可以借助二维前缀和 , 将一定范围内不同亮度的灯全部合并到一起 , 最后对于 每次询问 ,只需要遍历所有的亮度即可 。

    代码示例 :

    /*
     * Author:  renyi 
     * Created Time:  2017/8/29 9:23:49
     * File Name: 
     */
    #include <iostream>
    #include <cstdio>
    #include <cstdlib>
    #include <cstring>
    #include <cmath>
    #include <algorithm>
    #include <string>
    #include <vector>
    #include <stack>
    #include <queue>
    #include <set>
    #include <time.h>
    using namespace std;
    const int maxint = -1u>>1;
    #define Max(a,b) a>b?a:b
    #define Min(a,b) a>b?b:a
    #define ll long long
    int dp[105][105][15] ;
    
    int main() {
        int n , q , c ;
        int x , y , c1 ;
        
        while ( ~scanf ( "%d%d%d" , &n , &q , &c) ) {
            memset ( dp , 0 , sizeof(dp) ) ;
            for ( int i = 0 ; i < n ; i++ ) {
                scanf ( "%d%d%d" , &x , &y , &c1 ) ;
                dp[x][y][c1]++ ;
            }
            
            for ( int i = 1 ; i <= 100 ; i++ ) {
                for ( int j = 1 ; j <= 100 ; j++ ) {
                    for ( int k = 0 ; k <= 10 ; k++ ) {
                        dp[i][j][k] += dp[i-1][j][k]+dp[i][j-1][k]-dp[i-1][j-1][k] ;
                    }
                }
            }
            
            int t , x1 , y1 , x2 , y2 ;
            while ( q-- ) {
                scanf ( "%d%d%d%d%d" , &t , &x1 , &y1 , &x2 , &y2 ) ;
                
                int sum = 0 ;
                for ( int i = 0 ; i <= c ; i++ ) {
                    int s = dp[x2][y2][i] + dp[x1-1][y1-1][i] - dp[x1-1][y2][i] - dp[x2][y1-1][i] ;
                    int l = ( t + i ) % ( c + 1 ) ;
                    sum += s * l ;
                }
                printf ( "%d
    " , sum ) ;
            }
        }
        
        return 0;
    }
    
    东北日出西边雨 道是无情却有情
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  • 原文地址:https://www.cnblogs.com/ccut-ry/p/7446958.html
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