Improve

Signed-off-by: Leo Ma <begeekmyfriend@gmail.com>

Author: begeekmyfriend

205_isomorphic_strings/1

@@ -29,14 +29,13 @@ static bool dfs(struct graph_node *courses, int id, bool *takens, bool *touched)
     }
 }
 
-#define N 2000
-static struct graph_node courses[N];
-static bool takens[N];
-static bool touched[N];
-
 static bool canFinish(int numCourses, int** prerequisites, int prerequisitesRowSize, int prerequisitesColSize)
 {
     int i;
+    bool *takens = malloc(numCourses);
+    bool *touched = malloc(numCourses);
+    struct graph_node *courses = malloc(numCourses * sizeof(*courses));
+
     memset(courses, 0, numCourses * sizeof(*courses));
     memset(takens, false, numCourses * sizeof(bool));
     memset(touched, false, numCourses * sizeof(bool));

207_course_schedule/course_schedule.c

@@ -30,19 +30,18 @@ static bool dfs(struct graph_node *courses, int id, bool *takens, bool *touched,
     }
 }
 
-#define N 2000
-static int order[N];
-static struct graph_node courses[N];
-static bool takens[N];
-static bool touched[N];
-
 /**
  * Return an array of size *returnSize.
  * Note: The returned array must be malloced, assume caller calls free().
  */
 static int *findOrder(int numCourses, int** prerequisites, int prerequisitesRowSize, int prerequisitesColSize, int *returnSize)
 {
     int i;
+    int *order = malloc(numCourses * sizeof(int));
+    bool *takens = malloc(numCourses);
+    bool *touched = malloc(numCourses);
+    struct graph_node *courses = malloc(numCourses * sizeof(*courses));
+
     memset(courses, 0, numCourses * sizeof(*courses));
     memset(takens, false, numCourses * sizeof(bool));
     memset(touched, false, numCourses * sizeof(bool));

210_course_schedule_ii/course_schedule.c

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test slide_window.c

239_sliding_window_maximum/Makefile

@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+/**
+ * Return an array of size *returnSize.
+ * Note: The returned array must be malloced, assume caller calls free().
+ */
+int* maxSlidingWindow(int* nums, int numsSize, int k, int* returnSize)
+{
+    int i, head = 0, tail = 0;
+    int count = 0;
+    int *indexes = malloc(numsSize * sizeof(int));
+    int *results = malloc((numsSize - k + 1) * sizeof(int));
+
+    for (i = 0; i < numsSize; i++) {
+        /* monotonous decreasing */
+        while (tail > head && nums[i] >= nums[indexes[tail - 1]]) {
+            tail--;
+        }
+        indexes[tail++] = i;
+
+        if (indexes[head] <= i - k) {
+            head++;
+        }
+
+        if (i >= k - 1) {
+            results[count++] = nums[indexes[head]];
+        }
+    }
+
+    *returnSize = count;
+    return results;
+}
+
+int main(int argc, char **argv)
+{
+    if (argc < 2) {
+        fprintf(stderr, "Usage: ./test k n1 n2...\n");
+        exit(-1);
+    }
+
+    int i, size = argc - 2;
+    int k = atoi(argv[1]);
+    int *nums = malloc(size * sizeof(int));
+    for (i = 0; i < size; i++) {
+        nums[i] = atoi(argv[i + 2]);
+    }
+
+    int count = 0;
+    int *lists = maxSlidingWindow(nums, size, k, &count);
+    for (i = 0; i < count; i++) {
+        printf("%d ", lists[i]); 
+    }
+    printf("\n");
+    return 0;
+}