【UVa】10360 - Rat Attack

Problem here

Problem

Baaaam! Another deadly gas bomb explodes in Manhattan’s underworld. Rats have taken over the
sewerage and the city council is doing everything to get the rat population under control.
As you know, Manhattan is organized in a regular fashion with streets and avenues arranged like
a rectangular grid. Waste water drains run beneath the streets in the same arrangement and the rats
have always set up their nests below street intersections. The only viable method to extinguish them
is to use gas bombs like the one which has just exploded. However, gas bombs are not only dangerous
for rats. The skyscrapers above the explosion point have to be evacuated in advance and so the point
of rat attack must be chosen very carefully.
The gas bombs used are built by a company called American Catastrophe Management (ACM) and
they are sold under the heading of “smart rat gas”. They are smart because —when fired— the gas
spreads in a rectangular fashion through the under street canals. The strength of a gas bomb is given
by a number d which specifies the rectangular “radius” of the gas diffusion area. For example, the
figure shows what happens when a bomb with d = 1 explodes.
The area of interest consists of a discrete grid of 1025 × 1025 fields. Rat exterminator scouts have
given a detailed report on where rat populations of different sizes have built their nests. You are given
a gas bomb with strength d and your task is to find an explosion location for this gas bomb which
extinguishes the largest number of rats.
The best position is determined by the following criteria:
• The sum of all rat population sizes within the diffusion area of the gas bomb (given by d) is
maximal.
• If there is more than one of these best positions then the location with the “minimal” position
will be chosen. Positions are ordered first by their x coordinate and second by their y coordinate.
Formally, given a location (x1, y1) on the grid, a point (x2, y2) is within the diffusion area of a gas
bomb with strength d if the following equation holds:
max(abs(x2 − x1), abs(y2 − y1)) ≤ d

Input

The first line contains the number of scenarios in the input.
For each scenario the first line contains the strength d of the gas bomb in the scenario (1 ≤ d ≤ 50).
The second line contains the number n (1 ≤ n ≤ 20000) of rat populations. Then for every rat
population follows a line containing three integers separated by spaces for the position (x, y) and “size”
i of the population (1 ≤ i ≤ 255). It is guaranteed that position coordinates are valid (i.e., in the range
between 0 and 1024) and no position is given more than once.

Output

For every problem print a line containing the x and y coordinate of the chosen location for the gas
bomb, followed by the sum of the rat population sizes which will be extinguished. The three numbers
must be separated by a space.

Sample

Input:
1
1
2
4 4 10
6 6 20
Output:
5 5 30

Solution

由老鼠開始枚舉

    #include <iostream>
    #include <stdlib.h>
    #include "memory.h"
    using namespace std;
    int bomb;
    int killed[1025][1025];

    int main(){
        int scen;
        cin >> scen;
        while(scen--){
            memset(killed, 0, sizeof(killed));
            cin >> bomb;
            int rats;
            cin >> rats;
            while(rats--){
                int x, y, popu;
                cin >> x >> y >> popu;
                for(int i=x-bomb ; i<=x+bomb ; i++)
                    for(int j=y-bomb ; j<=y+bomb ; j++)
                        if(i >= 0 && i <= 1024 && j >= 0 && j <= 1024) 
                            killed[i][j] += popu;
            }
            int tmp = 0, tmpX, tmpY;
            for(int i=0 ; i<=1024 ; i++){
                for(int j=0 ; j<=1024 ; j++) {
                    if(killed[i][j] > tmp) {
                        tmp = killed[i][j];
                        tmpX = i, tmpY = j;
                    }
                }
            }
            cout << tmpX << " " << tmpY << " " << tmp << endl;
        }

        return 0;
    }