PAT A1091 Acute Stroke (30分)

題目鏈接：https://pintia.cn/problem-sets/994805342720868352/problems/994805375457411072

題目描述
One important factor to identify acute stroke (急性腦卒中) is the volume of the stroke core. Given the results of image analysis in which the core regions are identified in each MRI slice, your job is to calculate the volume of the stroke core.

輸入
Each input file contains one test case. For each case, the first line contains 4 positive integers: M, N, L and T, where M and N are the sizes of each slice (i.e. pixels of a slice are in an M×N matrix, and the maximum resolution is 1286 by 128); L (≤60) is the number of slices of a brain; and T is the integer threshold (i.e. if the volume of a connected core is less than T, then that core must not be counted).

Then L slices are given. Each slice is represented by an M×N matrix of 0’s and 1’s, where 1 represents a pixel of stroke, and 0 means normal. Since the thickness of a slice is a constant, we only have to count the number of 1’s to obtain the volume. However, there might be several separated core regions in a brain, and only those with their volumes no less than T are counted. Two pixels are connected and hence belong to the same region if they share a common side, as shown by Figure 1 where all the 6 red pixels are connected to the blue one.

輸出
For each case, output in a line the total volume of the stroke core.

樣例輸入
3 4 5 2
1 1 1 1
1 1 1 1
1 1 1 1
0 0 1 1
0 0 1 1
0 0 1 1
1 0 1 1
0 1 0 0
0 0 0 0
1 0 1 1
0 0 0 0
0 0 0 0
0 0 0 1
0 0 0 1
1 0 0 0

樣例輸出
26

代碼

#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
#include<cstdio>
using namespace std;
 
const int N = 129;
int map[1300][130][80];
bool vst[1300][130][80];
int m,n,l,t;
 
int dirX[6] = {1,0,-1,0,0,0}; 
int dirY[6] = {0,1,0,-1,0,0}; 
int dirZ[6] = {0,0,0,0,1,-1}; 
 
struct state{
	int x,y,z;
	state(int a,int b,int c){
		x = a;y = b;z = c;
	}
};
 
bool check(state s){
	if(s.x < 0 || s.x >= m || s.y < 0 || s.y >= n || s.z < 0 || s.z >= l)
		return false;
	if(vst[s.x][s.y][s.z] == true ||  map[s.x][s.y][s.z] == 0) return false;
	else
		return true;
}
 
int bfs(int a,int b,int c){
	int cnt = 0;
	state s(a,b,c);
	queue<state> que;
	que.push(s);
	vst[a][b][c] = true;
	while(!que.empty()){
		cnt++;
		state now = que.front();
		que.pop();
		for(int i=0;i<6;i++){
			state next = now;
			next.x = now.x + dirX[i];
			next.y = now.y + dirY[i];
			next.z = now.z + dirZ[i];
			if(check(next)){
				vst[next.x][next.y][next.z]	 = true;
				que.push(next);
			}
		}
	}
	if(cnt >= t)
		return cnt;
	else
		return 0;
}
 
int main(){
	cin>>m>>n>>l>>t;
	
	for(int i=0;i<l;i++)
		for(int j=0;j<m;j++)
			for(int k=0;k<n;k++)
				scanf("%d",&map[j][k][i]);
	int sum = 0;	
	for(int i=0;i<l;i++) 
		for(int j=0;j<m;j++)
			for(int k=0;k<n;k++){
				state s(j,k,i);
				if(check(s)){
					sum += bfs(j,k,i);			
				}
			}
	printf("%d",sum);
 
	return 0;
}