Add implementation for "Queen's Attack II" problem

This commit introduces a C program to solve the "Queen's Attack II" problem. It calculates the queen's possible moves on a chessboard while accounting for obstacles. The solution includes utility functions for input handling and processing the constraints.

Author: holman57

QueensAttack2.c

@@ -0,0 +1,246 @@
+#include <assert.h>
+#include <ctype.h>
+#include <limits.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+char* readline();
+char* ltrim(char*);
+char* rtrim(char*);
+char** split_string(char*);
+
+int parse_int(char*);
+
+/*
+ * Complete the 'queensAttack' function below.
+ *
+ * The function is expected to return an INTEGER.
+ * The function accepts following parameters:
+ *  1. INTEGER n
+ *  2. INTEGER k
+ *  3. INTEGER r_q
+ *  4. INTEGER c_q
+ *  5. 2D_INTEGER_ARRAY obstacles
+ */
+
+int queensAttack(int n, int k, int r_q, int c_q, int obstacles_rows, int obstacles_columns, int** obstacles) {
+    // Initialize movement limits in 8 directions
+    int up = n - r_q;
+    int down = r_q - 1;
+    int left = c_q - 1;
+    int right = n - c_q;
+
+    int top_left = (r_q - 1 < c_q - 1) ? r_q - 1 : c_q - 1;
+    int top_right = (r_q - 1 < n - c_q) ? r_q - 1 : n - c_q;
+    int bottom_left = (n - r_q < c_q - 1) ? n - r_q : c_q - 1;
+    int bottom_right = (n - r_q < n - c_q) ? n - r_q : n - c_q;
+
+    // Process each obstacle
+    for (int i = 0; i < k; i++) {
+        int obs_row = obstacles[i][0];
+        int obs_col = obstacles[i][1];
+
+        // Check if obstacle affects the column (up or down)
+        if (obs_col == c_q) {
+            if (obs_row > r_q) {
+                up = (obs_row - r_q - 1 < up) ? obs_row - r_q - 1 : up;
+            } else {
+                down = (r_q - obs_row - 1 < down) ? r_q - obs_row - 1 : down;
+            }
+        }
+        // Check if obstacle affects the row (left or right)
+        else if (obs_row == r_q) {
+            if (obs_col > c_q) {
+                right = (obs_col - c_q - 1 < right) ? obs_col - c_q - 1 : right;
+            } else {
+                left = (c_q - obs_col - 1 < left) ? c_q - obs_col - 1 : left;
+            }
+        }
+        // Check if obstacle affects diagonals
+        else if (abs(obs_row - r_q) == abs(obs_col - c_q)) {
+            // Top-left diagonal
+            if (obs_row < r_q && obs_col < c_q) {
+                top_left = (r_q - obs_row - 1 < top_left) ? r_q - obs_row - 1 : top_left;
+            }
+            // Top-right diagonal
+            else if (obs_row < r_q && obs_col > c_q) {
+                top_right = (r_q - obs_row - 1 < top_right) ? r_q - obs_row - 1 : top_right;
+            }
+            // Bottom-left diagonal
+            else if (obs_row > r_q && obs_col < c_q) {
+                bottom_left = (obs_row - r_q - 1 < bottom_left) ? obs_row - r_q - 1 : bottom_left;
+            }
+            // Bottom-right diagonal
+            else if (obs_row > r_q && obs_col > c_q) {
+                bottom_right = (obs_row - r_q - 1 < bottom_right) ? obs_row - r_q - 1 : bottom_right;
+            }
+        }
+    }
+
+    // Sum up all valid moves
+    return up + down + left + right + top_left + top_right + bottom_left + bottom_right;
+}
+
+int main()
+{
+    FILE* fptr = fopen(getenv("OUTPUT_PATH"), "w");
+
+    char** first_multiple_input = split_string(rtrim(readline()));
+
+    int n = parse_int(*(first_multiple_input + 0));
+
+    int k = parse_int(*(first_multiple_input + 1));
+
+    char** second_multiple_input = split_string(rtrim(readline()));
+
+    int r_q = parse_int(*(second_multiple_input + 0));
+
+    int c_q = parse_int(*(second_multiple_input + 1));
+
+    int** obstacles = malloc(k * sizeof(int*));
+
+    for (int i = 0; i < k; i++) {
+        *(obstacles + i) = malloc(2 * (sizeof(int)));
+
+        char** obstacles_item_temp = split_string(rtrim(readline()));
+
+        for (int j = 0; j < 2; j++) {
+            int obstacles_item = parse_int(*(obstacles_item_temp + j));
+
+            *(*(obstacles + i) + j) = obstacles_item;
+        }
+    }
+
+    int result = queensAttack(n, k, r_q, c_q, k, 2, obstacles);
+
+    fprintf(fptr, "%d\n", result);
+
+    fclose(fptr);
+
+    return 0;
+}
+
+char* readline() {
+    size_t alloc_length = 1024;
+    size_t data_length = 0;
+
+    char* data = malloc(alloc_length);
+
+    while (true) {
+        char* cursor = data + data_length;
+        char* line = fgets(cursor, alloc_length - data_length, stdin);
+
+        if (!line) {
+            break;
+        }
+
+        data_length += strlen(cursor);
+
+        if (data_length < alloc_length - 1 || data[data_length - 1] == '\n') {
+            break;
+        }
+
+        alloc_length <<= 1;
+
+        data = realloc(data, alloc_length);
+
+        if (!data) {
+            data = '\0';
+
+            break;
+        }
+    }
+
+    if (data[data_length - 1] == '\n') {
+        data[data_length - 1] = '\0';
+
+        data = realloc(data, data_length);
+
+        if (!data) {
+            data = '\0';
+        }
+    } else {
+        data = realloc(data, data_length + 1);
+
+        if (!data) {
+            data = '\0';
+        } else {
+            data[data_length] = '\0';
+        }
+    }
+
+    return data;
+}
+
+char* ltrim(char* str) {
+    if (!str) {
+        return '\0';
+    }
+
+    if (!*str) {
+        return str;
+    }
+
+    while (*str != '\0' && isspace(*str)) {
+        str++;
+    }
+
+    return str;
+}
+
+char* rtrim(char* str) {
+    if (!str) {
+        return '\0';
+    }
+
+    if (!*str) {
+        return str;
+    }
+
+    char* end = str + strlen(str) - 1;
+
+    while (end >= str && isspace(*end)) {
+        end--;
+    }
+
+    *(end + 1) = '\0';
+
+    return str;
+}
+
+char** split_string(char* str) {
+    char** splits = NULL;
+    char* token = strtok(str, " ");
+
+    int spaces = 0;
+
+    while (token) {
+        splits = realloc(splits, sizeof(char*) * ++spaces);
+
+        if (!splits) {
+            return splits;
+        }
+
+        splits[spaces - 1] = token;
+
+        token = strtok(NULL, " ");
+    }
+
+    return splits;
+}
+
+int parse_int(char* str) {
+    char* endptr;
+    int value = strtol(str, &endptr, 10);
+
+    if (endptr == str || *endptr != '\0') {
+        exit(EXIT_FAILURE);
+    }
+
+    return value;
+}