Passed: Whac-a-Mole

whac-a-mole/Makefile

@@ -0,0 +1,18 @@
+EXE=whac-a-moler
+CC=g++
+CFLAGS=-g -O2 -std=gnu++17
+LFLAGS=-lm
+WFLAGS=-Wall -Wextra -Weffc++ -Wpedantic
+OBJ=main.cpp
+
+
+.PHONY: clean test
+test: $(EXE)
+	./$(EXE)<d0 | diff --color=always a0 -
+
+$(EXE): $(OBJ)
+	$(CC) $(CFLAGS) -o $@ -static $(OBJ) $(LFLAGS) $(WFLAGS)
+
+clean:
+	rm -rf $(EXE)
+

whac-a-mole/a0

@@ -0,0 +1,2 @@
+4
+2

whac-a-mole/d0

@@ -0,0 +1,12 @@
+4 2 6
+0 0 1
+3 1 3
+0 1 2
+0 2 2
+1 0 2
+2 0 2
+5 4 3
+0 0 1
+1 2 1
+2 4 1
+0 0 0

whac-a-mole/main.cpp

@@ -0,0 +1,385 @@
+#include <stdio.h>
+#include <math.h>
+#include <assert.h>
+
+#include <string>
+using std::string;
+
+#include <iostream>
+using std::cout;
+
+#include <vector>
+using std::vector;
+#include <algorithm>
+
+void debug_indent(int lvl) {for (int i{0}; i < lvl; ++i) {cout << "   ";}}
+
+
+struct Mole
+{
+    int x;
+    int y;
+    int t;
+
+    bool operator<(const Mole& other) {
+        return this->t > other.t;
+    }
+};
+
+struct Move
+{
+    int x;
+    int y;
+
+    bool operator<(const Move& other) {
+        if (    (this->x < other.x) || 
+                (this->x == other.x && this->y < other.y)
+        ) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+};
+
+vector<Move> generate_moves(const int d)
+{
+    vector<Move> moves;
+    for (int i{-d}; i <= d; ++i) {
+        for (int j{-d}; j <= d; ++j) {
+            if ( (i*i + j*j) <= d*d) {
+                moves.push_back( {i,j} );
+    }}}
+
+    return moves;
+}
+
+
+struct Matrix
+{
+    bool *m;
+    size_t width;
+    int max_movement;
+    
+    Matrix(
+        size_t _width,
+        int _max_movement) :
+        m(nullptr),
+        width(_width),
+        max_movement(_max_movement)
+    {
+        m = (bool*) malloc( (width*width) * sizeof(bool) );
+        for (size_t i{0}; i < width*width; ++i) {
+            *(m+i) = false;
+        }
+    };
+    ~Matrix() {
+        delete m;
+    }
+
+
+    void set(int x, int y, bool val) {
+        size_t index = (x+max_movement)*width + (y+max_movement);
+        m[index] = val;
+    }
+
+    bool get(int x, int y) const {
+        size_t index = (x+max_movement)*width + (y+max_movement);
+        return m[index];
+    }
+
+    void reinit(
+            const int t,
+            vector<Mole>::const_iterator new_moles,
+            const vector<Mole>::const_iterator end_iter)
+    {
+        // Zero existing matrix
+        for (size_t i{0}; i < width*width; ++i) {
+            *(m+i) = false;
+        }
+        if (t != new_moles->t) { return; } // Exit after board clear if no moles are on board
+
+        int current_time = new_moles->t;
+        while (new_moles != end_iter && new_moles->t == current_time)
+        {
+            this->set(new_moles->x, new_moles->y, true);
+            ++new_moles;
+        }
+    }
+
+    void print()
+    {
+        for (size_t j{0}; j < width; ++j) {
+            for (size_t i{0}; i < width; ++i) {
+                printf("(%2lu,%2lu)=%d ", i, j, *((m+i*width)+j));
+            }
+            puts("");
+        }
+    }
+};
+
+const int MAX_T = 10;
+const int MAX_W = 20;
+const int MAX_MV = 5;
+
+
+struct Memo
+{
+    int max_hits[MAX_T][MAX_W + 2*MAX_MV][MAX_W + 2*MAX_MV];
+    const int max_time;
+    const int board_width;
+    const int max_movement;
+
+    Memo(
+        int _max_time,
+        int _board_width,
+        int _max_movement) : 
+        max_time(_max_time),
+        board_width(_board_width),
+        max_movement(_max_movement)
+    {
+        for (int i{0}; i < max_time; ++i) {
+            for (int j{0}; j < board_width+2*max_movement; ++j) {
+                for (int k{0}; k < board_width+2*max_movement; ++k) {
+                    max_hits[i][j][k] = 0;
+                }
+            }
+        }
+    }
+
+    bool is_inside(int t, int x, int y) const {
+        bool inside = (1 <= t && t <= max_time);
+        inside &= (-max_movement <= x && x < board_width+max_movement);
+        inside &= (-max_movement <= y && y < board_width+max_movement);
+
+        return inside;
+    }
+
+    void set(int t, int x, int y, int val) {
+        assert( this->is_inside(t, x, y) );
+        max_hits[t-1][x+max_movement][y+max_movement] = val;
+    }
+
+    int get(int t, int x, int y) const {
+        assert( this->is_inside(t, x, y) );
+        return max_hits[t-1][x+max_movement][y+max_movement];
+    }
+
+    void print() 
+    {
+        for (int i{0}; i < max_time; ++i) {
+            printf("T-%d:\n", i+1);
+            printf("  : ");
+            for(int k{0}; k < board_width+2*max_movement; ++k) {
+                printf("%3d|", k-max_movement);
+            }
+            puts("");
+            for (int j{0}; j < board_width+2*max_movement; ++j) {
+
+                printf("%3d: ", j-max_movement);
+                for (int k{0}; k < board_width+2*max_movement; ++k) {
+                    printf("%3d ", max_hits[i][j][k]);
+                }
+                puts("\n");
+            }
+            puts("");
+        }
+    }
+};
+
+int max(int a, int b) {
+    return (a < b) ? b : a;
+}
+
+int max_hits_from_position(
+        const int t,
+        const int max_t,
+        const int x,
+        const int y,
+        const Memo& max_hits,
+        const Matrix& active_moles,
+        const vector<Move>& moves)
+{
+    int current_max = 0;
+    for (const auto& move : moves)
+    {
+        int hits = 0;
+
+        const int new_x = x + move.x;
+        const int new_y = y + move.y;
+        if ( !max_hits.is_inside(t, new_x, new_y) ) {
+            continue; // Check new move if current moves whac way off board
+        }
+
+        // Check current pos
+        if ( active_moles.get(x, y) ) {
+            ++hits;
+        }
+
+        if ( !(move.x == 0 && move.y == 0) )
+        {
+            // Yes I know, it is lazy
+            if (    (move.x%4 == 0 && move.y == 0) ||
+                    (move.y%4 == 0 && move.x == 0))
+            {
+                const int it_x = (move.x/4);
+                const int it_y = (move.y/4);
+
+                if ( active_moles.get( (x + 1*it_x), (y + 1*it_y) ) ) {
+                    ++hits;
+                }
+                if ( active_moles.get( (x + 2*it_x), (y + 2*it_y) ) ) {
+                    ++hits;
+                }
+                if ( active_moles.get( (x + 3*it_x), (y + 3*it_y) ) ) {
+                    ++hits;
+                }
+            }
+            else if (move.x%2 == 0 && move.y%2 == 0)
+            {
+                const int it_x = (move.x/2);
+                const int it_y = (move.y/2);
+
+                if ( active_moles.get( (x + 1*it_x), (y + 1*it_y) ) ) {
+                    ++hits;
+                }
+            }
+            else if (move.x%3 == 0 && move.y%3 == 0)
+            {
+                const int it_x = (move.x/3);
+                const int it_y = (move.y/3);
+
+                if ( active_moles.get( (x + 1*it_x), (y + 1*it_y) ) ) {
+                    ++hits;
+                }
+                if ( active_moles.get( (x + 2*it_x), (y + 2*it_y) ) ) {
+                    ++hits;
+                }
+            }
+            else if (   (move.x%5 == 0 && move.y == 0) ||
+                        (move.y%5 == 0 && move.x == 0))
+            {
+                const int it_x = (move.x/5);
+                const int it_y = (move.y/5);
+
+                if ( active_moles.get( (x + 1*it_x), (y + 1*it_y) ) ) {
+                    ++hits;
+                }
+                if ( active_moles.get( (x + 2*it_x), (y + 2*it_y) ) ) {
+                    ++hits;
+                }
+                if ( active_moles.get( (x + 3*it_x), (y + 3*it_y) ) ) {
+                    ++hits;
+                }
+                if ( active_moles.get( (x + 4*it_x), (y + 4*it_y) ) ) {
+                    ++hits;
+                }
+            }
+
+            // Check pos at end of line: new_x and new_y
+            if ( active_moles.get(new_x, new_y) ) {
+                ++hits;
+            }
+        }
+
+        // Add destination if not at last timestep
+        if (t < max_t) {
+            hits += max_hits.get(t+1, new_x, new_y);
+        }
+
+        current_max = max(hits, current_max);
+    }
+
+    return current_max;
+}
+
+void test_case(
+        const int n, // Width of board
+        const int d, // Max distance of a move
+        const int n_moles)
+{
+    int b_width = n + 2*d;
+    Matrix active_moles(b_width, d);
+
+    vector<Mole> moles;
+    {
+        int x, y, t;
+        for (int i{0}; i < n_moles; ++i) {
+            scanf("%d %d %d\n", &x, &y, &t);
+            moles.push_back( {x, y, t} );
+        }
+    }
+    std::sort(moles.begin(), moles.end());
+  
+    int timestamp_last_mole = moles.begin()->t;
+  
+
+    Memo max_hits(timestamp_last_mole, n, d);
+
+    // Generate all valid moves for this test case
+    vector<Move> moves = generate_moves(d);
+
+    // Iterator to beginning of sequence of moles for the current timestamp
+    vector<Mole>::const_iterator current_moles = moles.begin();
+
+    int first_t = 1;
+    for (int t{timestamp_last_mole}; 1 <= t; --t)
+    {
+        // Iterate to moles on this timestep or earlier one (backwards iteration through time)
+        while ( (current_moles != moles.end()) &&
+                (current_moles->t) > t)
+        {
+            ++current_moles;
+        }
+       
+        // Break out early if mole list is emptied
+        if (current_moles == moles.end())
+        {
+            first_t = t+1;
+            break;
+        }
+        
+        // Re-initialize active_moles: zero and set new moles
+        active_moles.reinit(t, current_moles, moles.end());
+
+        // 2D iteration over all possible start positions in (and outside) the board
+        for (int i{-d}; i < n+d; ++i) {
+            for (int j{-d}; j < n+d; ++j) {
+
+                int max_val = max_hits_from_position(
+                        t, timestamp_last_mole,
+                        i, j,
+                        max_hits,
+                        active_moles,
+                        moves);
+                max_hits.set(t, i, j, max_val);
+            }
+        }
+
+    }
+
+    int max_val = 0;
+    for (int i{-d}; i < n+d; ++i) {
+        for (int j{-d}; j < n+d; ++j) {
+            int val = max_hits.get(first_t, i, j);
+            if (max_val < val) {
+                max_val = val;
+            }
+        }
+    }
+    printf("%d\n", max_val);
+}
+
+int main()
+{
+    int n, d, m;
+
+    while(1)
+    {
+        scanf("%d %d %d\n", &n, &d, &m);
+        if (n+d+m == 0) { break; } // All zeroes (no negative values in file)
+
+        test_case(n, d, m);
+    }
+}
+