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Signed-off-by: begeekmyfriend <begeekmyfriend@gmail.com>
1 parent ef987c0 commit 934b7b7

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-407
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29 files changed

+277
-407
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‎053_maximum_subarray/max_subarray.c

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -2,15 +2,15 @@
22
#include <stdlib.h>
33
#include <limits.h>
44

5-
static int recursive(int *nums, int lo, int hi)
5+
static int partition(int *nums, int lo, int hi)
66
{
77
if (lo == hi) {
88
return nums[lo];
99
}
1010

1111
int ce = (hi - lo) / 2;
12-
int left_max = recursive(nums, lo, lo + ce);
13-
int right_max = recursive(nums, hi - ce, hi);
12+
int left_max = partition(nums, lo, lo + ce);
13+
int right_max = partition(nums, hi - ce, hi);
1414

1515
int i;
1616
int left_border = 0, left_border_max = INT_MIN;
@@ -48,7 +48,7 @@ static int maxSubArray(int* nums, int numsSize)
4848
}
4949
return max;
5050
#else
51-
return recursive(nums, 0, numsSize - 1);
51+
return partition(nums, 0, numsSize - 1);
5252
#endif
5353
}
5454

‎054_spiral_matrix/spiral_matrix.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -60,9 +60,9 @@ int main(int argc, char **argv)
6060
mat[i] = malloc(col * sizeof(int));
6161
for (j = 0; j < col; j++) {
6262
mat[i][j] = ++count;
63-
printf("%d ", mat[i][j]);
63+
printf("%d ", mat[i][j]);
6464
}
65-
printf("\n");
65+
printf("\n");
6666
}
6767
int *nums = spiralOrder(mat, row, col);
6868
for (i = 0; i < row * col; i++) {

‎055_jump_game/jump_game.c

Lines changed: 12 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -2,24 +2,22 @@
22
#include <stdlib.h>
33
#include <stdbool.h>
44

5-
static bool canJump(int* nums, int numsSize) {
6-
if (numsSize == 0) return false;
5+
static inline int max(int a, int b)
6+
{
7+
return a > b ? a : b;
8+
}
79

8-
int i = numsSize - 1, j;
9-
while (i > 0) {
10-
if (nums[--i] == 0) {
11-
for (j = i - 1; j >= 0; j--) {
12-
if (nums[j] > i - j) {
13-
break;
14-
}
15-
}
16-
if (j == -1) {
17-
return false;
18-
}
10+
static bool canJump(int* nums, int numsSize)
11+
{
12+
int i, pos = 0;
13+
for (i = 0; i < numsSize - 1; i++) {
14+
if (pos < i || pos >= numsSize - 1) {
15+
break;
1916
}
17+
pos = max(i + nums[i], pos);
2018
}
2119

22-
return true;
20+
return pos >= numsSize - 1;
2321
}
2422

2523
int main(int argc, char **argv)

‎060_permutation_sequence/permutation_sequence.c

Lines changed: 15 additions & 40 deletions
Original file line numberDiff line numberDiff line change
@@ -2,59 +2,34 @@
22
#include <stdlib.h>
33
#include <string.h>
44

5-
static void reverse(int *a, int size)
5+
static int factorial(int n)
66
{
7-
int left = 0;
8-
int right = size - 1;
9-
while (left < right) {
10-
int tmp = a[left];
11-
a[left] = a[right];
12-
a[right] = tmp;
13-
left++;
14-
right--;
7+
if (n == 0) {
8+
return 0;
9+
} else if (n == 1) {
10+
return 1;
11+
} else {
12+
return n * factorial(n - 1);
1513
}
1614
}
1715

18-
void nextPermutation(int* nums, int numsSize) {
19-
if (numsSize <= 1) {
20-
return;
21-
}
22-
23-
int *p = nums + numsSize - 1;
24-
int *q = nums + numsSize - 1;
25-
26-
while (p != nums && *(p - 1) >= *p) {
27-
p--;
28-
}
29-
30-
if (p != nums) {
31-
int n = *(p - 1);
32-
while (*q <= n) {
33-
q--;
34-
}
35-
36-
int tmp = *q;
37-
*q = *(p - 1);
38-
*(p - 1) = tmp;
39-
}
40-
reverse(p, numsSize - (p - nums));
41-
}
42-
43-
static char* getPermutation(int n, int k) {
16+
static char* getPermutation(int n, int k)
17+
{
4418
int i;
4519
int *permutation = malloc(n * sizeof(int));
4620
for (i = 0; i < n; i++) {
4721
permutation[i] = i + 1;
4822
}
49-
while (--k > 0) {
50-
nextPermutation(permutation, n);
51-
}
23+
5224
char *result = malloc(n + 1);
5325
for (i = 0; i < n; i++) {
54-
result[i] = permutation[i] + '0';
26+
int fac = factorial(n - i - 1);
27+
int j = k > 1 ? (k - 1) / fac : 0;
28+
result[i] = permutation[j] + '0';
29+
k -= j * fac;
30+
memmove(permutation + j, permutation + j + 1, (n - j) * sizeof(int));
5531
}
5632
result[n] = '\0';
57-
free(permutation);
5833
return result;
5934
}
6035

‎062_unique_path/unique_path.c

Lines changed: 2 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -1,33 +1,8 @@
11
#include <stdio.h>
22
#include <stdlib.h>
33

4-
static void valid_path_recursive(int col, int m, int row, int n, int *count)
4+
static int uniquePaths(int m, int n)
55
{
6-
if (col == m - 1 && row == n - 1) {
7-
(*count)++;
8-
} else {
9-
if (m > n) {
10-
if (col < m - 1) {
11-
valid_path(col + 1, m, row, n, count);
12-
}
13-
if (row < n - 1) {
14-
valid_path(col, m, row + 1, n, count);
15-
}
16-
} else {
17-
if (col < m - 1) {
18-
valid_path(col + 1, m, row, n, count);
19-
}
20-
if (row < n - 1) {
21-
valid_path(col, m, row + 1, n, count);
22-
}
23-
}
24-
}
25-
}
26-
27-
static int uniquePaths(int m, int n) {
28-
//int count = 0;
29-
//valid_path(0, m, 0, n, &count);
30-
//return count;
316
int row, col;
327
int *grids = malloc(m * n * sizeof(int));
338
for (col = 0; col < m; col++) {
@@ -41,9 +16,7 @@ static int uniquePaths(int m, int n) {
4116
grids[row * m + col] = grids[row * m + col - 1] + grids[(row - 1) * m + col];
4217
}
4318
}
44-
int result = grids[m * n - 1];
45-
free(grids);
46-
return result;
19+
return grids[m * n - 1];
4720
}
4821

4922
int main(int argc, char **argv)

‎064_minumum_path_sum/minimum_path_sum.c

Lines changed: 8 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,9 +1,14 @@
11
#include <stdio.h>
22
#include <stdlib.h>
33
#include <string.h>
4-
#include <limits.h>
54

6-
int minPathSum(int** grid, int gridRowSize, int gridColSize) {
5+
static inline int min(int a, int b)
6+
{
7+
return a < b ? a : b;
8+
}
9+
10+
int minPathSum(int** grid, int gridRowSize, int gridColSize)
11+
{
712
int i, j;
813
int **dp = malloc(gridRowSize * sizeof(int *));
914
for (i = 0; i < gridRowSize; i++) {
@@ -23,11 +28,9 @@ int minPathSum(int** grid, int gridRowSize, int gridColSize) {
2328
dp[0][i] = sum;
2429
}
2530

26-
int min = INT_MAX;
2731
for (i = 1; i < gridRowSize; i++) {
2832
for (j = 1; j < gridColSize; j++) {
29-
int n = dp[i - 1][j] < dp[i][j - 1] ? dp[i - 1][j] : dp[i][j - 1];
30-
dp[i][j] = n + grid[i][j];
33+
dp[i][j] = grid[i][j] + min(dp[i - 1][j], dp[i][j - 1]);
3134
}
3235
}
3336

‎065_valid_number/valid_number.c

Lines changed: 29 additions & 48 deletions
Original file line numberDiff line numberDiff line change
@@ -1,57 +1,38 @@
11
#include <stdio.h>
22
#include <stdlib.h>
33
#include <stdbool.h>
4+
#include <ctype.h>
45

5-
static bool isNumber(const char *s) {
6-
bool point = false;
7-
bool hasE = false;
8-
9-
//trim the space
10-
while(isspace(*s)) s++;
11-
//check empty
12-
if (*s == '\0' ) return false;
13-
//check sign
14-
if (*s=='+' || *s=='-') s++;
15-
16-
const char *head = s;
17-
for(; *s!='\0'; s++){
18-
// if meet point
19-
if ( *s == '.' ){
20-
if ( hasE == true || point == true){
21-
return false;
22-
}
23-
if ( s == head && !isdigit(*(s+1)) ){
24-
return false;
25-
}
26-
point = true;
27-
continue;
28-
}
29-
//if meet "e"
30-
if ( *s == 'e' ){
31-
if ( hasE == true || s == head) {
32-
return false;
33-
}
34-
s++;
35-
if ( *s=='+' || *s=='-' ) s++;
36-
if ( !isdigit(*s) ) return false;
37-
38-
hasE = true;
39-
continue;
40-
}
41-
//if meet space, check the rest chars are space or not
42-
if (isspace(*s)){
43-
for (; *s != '\0'; s++){
44-
if (!isspace(*s)) return false;
45-
}
46-
return true;
47-
}
48-
if ( !isdigit(*s) ) {
49-
return false;
6+
static bool isNumber(const char *s)
7+
{
8+
while (*s == ' ')
9+
++s;
10+
bool if_find_num = false;
11+
if (*s == '-' || *s == '+')
12+
++s;
13+
while (isdigit(*s)) {
14+
if_find_num = true;
15+
++s;
16+
}
17+
if (*s == '.')
18+
++s;
19+
while (isdigit(*s)) {
20+
if_find_num = true;
21+
++s;
22+
}
23+
if (if_find_num == true && *s == 'e') {
24+
++s;
25+
if (*s == '+' || *s == '-')
26+
++s;
27+
if_find_num = false;
28+
while (isdigit(*s)) {
29+
if_find_num = true;
30+
++s;
5031
}
51-
5232
}
53-
54-
return true;
33+
while (*s == ' ')
34+
++s;
35+
return *s == '\0' && if_find_num == true;
5536
}
5637

5738
int main(int argc, char** argv)

‎071_simplify_path/simplify_path.c

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,8 @@
22
#include <stdlib.h>
33
#include <string.h>
44

5-
static char* simplifyPath(char* path) {
5+
static char* simplifyPath(char* path)
6+
{
67
int len = strlen(path);
78
if (len == 0) {
89
return path;

‎072_edit_distance/edit_distance.c

Lines changed: 6 additions & 39 deletions
Original file line numberDiff line numberDiff line change
@@ -4,41 +4,6 @@
44
#include <string.h>
55

66
/*
7-
* Dynamic Programming
8-
*
9-
* Definitaion
10-
*
11-
* m[i][j] is minimal distance from word1[0..i] to word2[0..j]
12-
*
13-
* So,
14-
*
15-
* 1) if word1[i] == word2[j], then m[i][j] == m[i-1][j-1].
16-
*
17-
* 2) if word1[i] != word2[j], then we need to find which one below is minimal:
18-
*
19-
* min( m[i-1][j-1], m[i-1][j], m[i][j-1] )
20-
*
21-
* and +1 - current char need be changed.
22-
*
23-
* Let's take a look m[1][2] : "a" => "ab"
24-
*
25-
* +---+ +---+
26-
* ''=> a | 1 | | 2 | '' => ab
27-
* +---+ +---+
28-
*
29-
* +---+ +---+
30-
* a => a | 0 | | 1 | a => ab
31-
* +---+ +---+
32-
*
33-
* To know the minimal distance `a => ab`, we can get it from one of the following cases:
34-
*
35-
* 1) delete the last char in word1, minDistance( '' => ab ) + 1
36-
* 2) delete the last char in word2, minDistance( a => a ) + 1
37-
* 3) change the last char, minDistance( '' => a ) + 1
38-
*
39-
*
40-
* For Example:
41-
*
427
* word1="abb", word2="abccb"
438
*
449
* 1) Initialize the DP matrix as below:
@@ -56,9 +21,13 @@
5621
* a 1 0 1 2 3 4
5722
* b 2 1 0 1 2 3
5823
* b 3 2 1 1 2 2
59-
*
6024
*/
6125

26+
static inline int min(int a, int b)
27+
{
28+
return a < b ? a : b;
29+
}
30+
6231
static int minDistance(char* word1, char* word2)
6332
{
6433
int i, j;
@@ -82,9 +51,7 @@ static int minDistance(char* word1, char* word2)
8251
if (word1[i - 1] == word2[j - 1]) {
8352
dp[i][j] = dp[i - 1][j - 1];
8453
} else {
85-
int min = dp[i - 1][j] > dp[i][j - 1] ? dp[i][j - 1] : dp[i - 1][j];
86-
dp[i][j] = min > dp[i - 1][j - 1] ? dp[i - 1][j - 1] : min;
87-
dp[i][j] += 1;
54+
dp[i][j] = 1 + min(dp[i - 1][j - 1], min(dp[i - 1][j], dp[i][j - 1]));
8855
}
8956
}
9057
}

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