diff options
Diffstat (limited to 'jump_game4.c')
-rw-r--r-- | jump_game4.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/jump_game4.c b/jump_game4.c new file mode 100644 index 0000000..27380b8 --- /dev/null +++ b/jump_game4.c @@ -0,0 +1,97 @@ +// 1345. Jump Game IV +#include "lib/uthash/src/uthash.h" +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +/* + * given array of integers 'arr', you are initially positioned at first index of + * array. in one step, you can jump from index 'i' to index 'j'. return minimum + * number of steps to reach lat index of array. notice, you cannot jump outside + * of array at any time. + */ + +typedef struct { + int key; + struct list_node *ptr; + UT_hash_handle hh; +} node; + +typedef struct { + int val; + int *next; +} list_node; + +typedef struct { + int pos; + int step; +} status; + +int minJumps(int *arr, int arr_size) { + if (arr_size <= 1) + return 1; + status obj[arr_size]; + int visited[arr_size]; + memset(visited, 0, arr_size * sizeof(int)); + node *hash = NULL, *s; + struct list_node *tp; + for (int i = 0; i < arr_size; i++) { + HASH_FIND_INT(hash, &arr[i], s); + if (!s) { + s = (node *)calloc(1, sizeof(node)); + s->key = arr[i]; + HASH_ADD_INT(hash, key, s); + } + tp = (struct list_node *)calloc(1, sizeof(struct list_node)); + tp->val = i; + tp->next = s->ptr; + s->ptr = tp; + } + int top = 1, left = 0, pos, val; + obj[0].step = obj[0].pos = 0; + visited[0] = 1; + while (left < top) { + if (obj[left].pos == arr_size - 1) + break; + val = arr[obj[left].pos]; + HASH_FIND_INT(hash, &val, s); + if (s) { + tp = s->ptr; + while (tp) { + pos = tp->val; + if (!visited[pos]) { + visited[pos] = 1; + obj[top].step = obj[left].step + 1; + obj[top].pos = pos; + top++; + } + tp = tp->next; + } + HASH_DEL(hash, s); + } + for (int i = 0; i < 2; i++) { + pos = obj[left].pos + (i ? 1 : -1); + if (pos < 0 || pos >= arr_size) + continue; + if (visited[pos]) + continue; + obj[top].step = obj[left].step + 1; + obj[top].pos = pos; + visited[pos] = 1; + top++; + } + left++; + } + free(tp); + return obj[left].step; +} + +int main() { + int a1[] = {100, -23, -23, 404, 100, 23, 23, 23, 3, 404}; + int a2[] = {7}; + int a3[] = {7, 6, 9, 6, 9, 6, 9, 7}; + printf("%d\n", minJumps(a1, sizeof(a1) / sizeof(a1[0]))); // expect: 3 + printf("%d\n", minJumps(a2, sizeof(a2) / sizeof(a2[0]))); // expect: 0 + printf("%d\n", minJumps(a3, sizeof(a3) / sizeof(a3[0]))); // expect: 1 +} |