graph floodfill

Author: ivorynoise

Diff for: 469-d.cpp

@@ -0,0 +1,53 @@
+#include <bits/stdc++.h>
+using namespace std;
+typedef long long ll;
+typedef vector<ll> vi;
+typedef vector<vi> vvi;
+const int mod = 1000000007;
+const int sze = 100010;
+int dr[] = {1, 1, 0, -1, -1, -1, 0, 1};
+int dc[] = {0, 1, 1, 1, 0, -1, -1 , -1};
+char g[110][110];
+char t[110][110];
+
+int m, n;		//no of vertices
+
+int floodFill(int r, int c, char c1, char c2) {
+	if (r >= n || r < 0 || c >= m || c < 0 || t[r][c] == c2) return 0;
+
+	int ans = 1;
+	if (t[r][c] == c1) t[r][c] = c2;	//visited
+
+	for (int i = 0; i  < 8; ++i) {
+		ans += floodFill(r + dr[i], c + dc[i], c1, c2);
+	}
+	// g[r][c] = c1;	//backtracking can't be used because 1 cell at be visited in one go
+	//Once visited it must not be visited again
+	return ans;
+
+}
+
+int main() {
+	// freopen("in","r", stdin);
+	int t1;
+	cin >> t1;
+
+	cin.getline(g[0], 100);	//consumes endl
+	cin.getline(g[0], 100);	//consumes blank line
+
+	while (t1--) {
+		int i = 0;	//curline
+		m = n = 0;
+		while (isalpha(cin.peek()) && cin.getline(g[i++], 100)) n++;	//fills the matrix
+		m = strlen(g[0]);
+		int r, c;
+		char rowCol[100];
+		while (cin.getline(rowCol, 100) && strlen(rowCol) != 0) {
+			sscanf(rowCol, "%d%d", &r, &c);
+			copy(&g[0][0], &g[110][0], &t[0][0]); //use copy with containers
+			// memcpy(t, g, sizeof g);
+			cout << floodFill(--r, --c, 'W', 'L') << "\n";
+		}
+		if (t1) cout << "\n";
+	}
+}