Create CATM_BFS.cpp

CATM_BFS.cpp

@@ -0,0 +1,109 @@
+//Solution for http://www.spoj.com/problems/CATM/
+#include <iostream>
+#include <vector>
+#include <queue>
+#include <cstdio>
+#include <cstdlib>
+
+using namespace std;
+
+const int dx[] = {1, -1, 0, 0};
+const int dy[] = {0, 0, -1, 1};
+
+struct Cell {
+    int row, column;
+};
+
+int n, m, k;
+Cell mouse, cat1, cat2;
+
+vector<vector<int>> field;
+
+void Mark(Cell cell) { field[cell.row][cell.column] = 0; }
+
+int Distant(const Cell &cell1, const Cell &cell2){
+    return abs(cell1.row - cell2.row) + abs(cell1.column - cell2.column);
+}
+
+bool ShouldMoveTo(const Cell &cell){
+    if(Distant(mouse, cell) < Distant(cat1, cell) && Distant(mouse, cell) < Distant(cat2, cell))
+        return true;
+    return false;
+}
+
+void InitBoard() {
+    scanf("%d%d%d", &n, &m, &k);
+
+    field = vector<vector<int>>(n + 2);
+    for (int row = 0; row < n + 2; ++row) {
+        for (int column = 0; column < m + 2; ++column)
+            field[row].push_back(0);
+    }
+}
+
+void ResetVisited() {
+    for (int row = 1; row < n + 1; ++row) {
+        for (int column = 1; column < m + 1; ++column)
+            field[row][column] = 1;
+    }
+}
+
+void Init() {
+    scanf("%d %d %d %d %d %d", &mouse.row, &mouse.column, &cat1.row, &cat1.column,
+          &cat2.row, &cat2.column);
+
+    Mark(mouse);
+    Mark(cat1);
+    Mark(cat2);
+}
+
+bool IsMouseEscaped(Cell cell) {
+    if (cell.row == 1 || cell.row == n || cell.column == 1 || cell.column == m)
+        return true;
+    return false;
+}
+
+bool Bfs() {
+    if (IsMouseEscaped(mouse)){
+        return true;
+    }
+    int step = 0;
+    queue<Cell> q;
+    q.push(mouse);
+    Mark(mouse);
+    while (!q.empty()) {
+        Cell current_cell = q.front();
+        q.pop();
+
+        for (int dir = 0; dir < 4; ++dir) {
+            int next_row = current_cell.row + dx[dir];
+            int next_column = current_cell.column + dy[dir];
+
+            if (field[next_row][next_column]) {
+                Cell new_cell = {next_row, next_column};
+                if(ShouldMoveTo(new_cell)) {
+                    if (IsMouseEscaped(new_cell)) {
+                        return true;
+                    }
+                    Mark(new_cell);
+                    q.push(new_cell);
+                }
+            }
+        }
+    }
+    return false;
+}
+
+int main() {
+    InitBoard();
+    for (int i = 0; i < k; ++i) {
+        ResetVisited();
+        Init();
+        if (Bfs())
+            printf("YES\n");
+        else
+            printf("NO\n");
+        ResetVisited();
+    }
+    return 0;
+}