dfs：

//DFS
#include <bits/stdc++.h>
using namespace std;
const int N = 105;
int a[N][N], n, m;
int dx[4] = {-1, 1, 0, 0};
int dy[4] = {0, 0, -1, 1};

void dfs(int x, int y) {
    a[x][y] = 0;
    for (int i = 0; i < 4; i++) {
        int nx = x + dx[i];
        int ny = y + dy[i];
        if (nx < 1 || nx > n || ny < 1 || ny > m) continue;
        if (a[nx][ny] == 0) continue;
        dfs(nx, ny);
    }
}

int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++) {
            char c;
            cin >> c;
            a[i][j] = c - '0';
        }
    int sum = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++) {
            if (a[i][j] > 0) {
                dfs(i, j);
                sum++;
            }
        }
    cout << sum;
    return 0;
}

bfs：

//BFS
#include <bits/stdc++.h>
using namespace std;
const int N = 105;
int a[N][N], n, m;
int dx[4] = {-1, 1, 0, 0};
int dy[4] = {0, 0, -1, 1};
struct Point {
    int x, y;
};

void bfs(int x, int y) {
    queue<Point> q;
    q.push({x, y});
    a[x][y] = 0;
    while (q.size()) {
        Point p = q.front();
        q.pop();
        for (int i = 0; i < 4; i++) {
            int nx = p.x + dx[i];
            int ny = p.y + dy[i];
            if (nx < 1 || nx > n || ny < 1 || ny > m) continue;
            if (a[nx][ny] == 0) continue;
            a[nx][ny] = 0;
            q.push({nx, ny});
        }
    }
}

int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++) {
            char c;
            cin >> c;
            a[i][j] = c - '0';
        }
    int sum = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++) {
            if (a[i][j] > 0) {
                bfs(i, j);
                sum++;
            }
        }
    cout << sum;
    return 0;
}