独立岛问题的BFS，DFS求解
#include
#include
using namespace std;
#define _CRT_SECURE_NO_WARNINGS
#define MAX 20
#define queue_init (head=tail=0)
#define queue_is_empty (head==tail)
#define en_queue(x) (queue[tail++]=x)
#define de_queue (queue[head++])
struct point{
int x;
int y;
};
struct point queue[MAX*MAX];
int head, tail;
int a[] = { 1, -1, 0, 0 };
int b[] = { 0, 0, 1, -1 };
int N, M;
int map[MAX][MAX], vis[MAX][MAX];
int Ans;
int color;
int sum;
int maxmin;
void bfs(int flag,int i, int j){
queue_init;
point start;
start.x = i;
start.y = j;
en_queue(start);
map[start.x][start.y] = flag;
vis[start.x][start.y] = 1;
sum=1;
while (!queue_is_empty){
point p = de_queue;
for (int k = 0; k < 4; k++){
point next;
next.x = p.x + a[k];
next.y = p.y + b[k];
if (next.x<1 || next.x>N || next.y<1 || next.y>M) continue;
if (vis[next.x][next.y] == 1) continue;
if (map[next.x][next.y]>0){
map[next.x][next.y] = flag;
sum++;
vis[next.x][next.y] == 1;
en_queue(next);
}
}
}
maxmin = sum > maxmin ? sum : maxmin;
}
int main(){
freopen("input.txt","r",stdin);
int T;
cin >> T;
for (int t = 1; t <= T; t++){
color = 0;
cin >> N >> M;
for (int i = 1; i <= N; i++){
for (int j = 1; j <= M; j++){
cin >> map[i][j];
}
}
for (int i = 1; i <= N; i++){
for (int j = 1; j <= M; j++){
if (map[i][j] > 0){
bfs(--color,i,j);
}
}
}
cout << "#" << t << " " << -color <<" "<< maxmin<
using namespace std;
#define _CRT_SECURE_NO_WARNINGS
int T, N, M, sum,max,a[20][20], book[20][20];
int Next[4][2] = { { 0, 1 }, { 1, 0 }, { 0, -1 }, { -1, 0 } };
void dfs(int x, int y, int color){
int tx, ty, k;
//染色当前坐标
a[x][y] = color;
//循环
for (k = 0; k <= 3; k++){
//新坐标
tx = x + Next[k][0];
ty = y + Next[k][1];
//判断边界
if (tx<1 || tx>N || ty < 1 || ty>M) continue;
//判断是否可走
if (a[tx][ty] >= 1 && book[tx][ty] == 0){
sum++;
//标记走过
book[tx][ty] = 1;
//开始尝试下一个点
dfs(tx,ty,color);
if (sum > max) max = sum;
}
}
return;
}
int main(){
int i, j, t, num = 0;
freopen("input.txt","r",stdin);
setbuf(stdout, NULL);
//输入数据
cin >> T;
for (t = 1; t <= T; t++){
cin >> N >> M;
for (i = 1; i <= N; i++)
for (j = 1; j <= M; j++)
cin >> a[i][j];
//判断传入dfs函数的参数，调用dfs()
for (i = 1; i <= N; i++){
for (j = 1; j <= M; j++){
if (a[i][j] >= 1){
num--;
book[i][j] = 1;
dfs(i, j, num);
}
}
}
//输出
cout << -num << " " << max << endl;
for (i = 1; i <= N; i++){
for (j = 1; j <= M; j++)
printf("%3d", a[i][j]);
cout << endl;
}
}
while (1);
return 0;
}
