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CyC2018 2018-04-29 16:12:03 +08:00
parent 889f6645f3
commit 775d62a4ad
1 changed files with 38 additions and 30 deletions
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notes/Leetcode 题解.md
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@ -629,9 +629,12 @@ public int[] twoSum(int[] numbers, int target) {
int i = 0, j = numbers.length - 1;
while (i < j) {
int sum = numbers[i] + numbers[j];
if (sum == target) return new int[]{i + 1, j + 1};
else if (sum < target) i++;
else j--;
if (sum == target)
return new int[]{i + 1, j + 1};
else if (sum < target)
i++;
else
j--;
}
return null;
}
@ -654,9 +657,12 @@ public boolean judgeSquareSum(int c) {
int i = 0, j = (int) Math.sqrt(c);
while (i <= j) {
int powSum = i * i + j * j;
if (powSum == c) return true;
if (powSum > c) j--;
else i++;
if (powSum == c)
return true;
if (powSum > c)
j--;
else
i++;
}
return false;
}
@ -681,11 +687,11 @@ public String reverseVowels(String s) {
while (i <= j) {
char ci = s.charAt(i);
char cj = s.charAt(j);
if (!vowels.contains(ci)) {
if (!vowels.contains(ci))
result[i++] = ci;
} else if (!vowels.contains(cj)) {
else if (!vowels.contains(cj))
result[j--] = cj;
} else {
else {
result[i++] = cj;
result[j--] = ci;
}
@ -709,20 +715,18 @@ Explanation: You could delete the character 'c'.
```java
public boolean validPalindrome(String s) {
int i = -1, j = s.length();
while (++i < --j) {
if (s.charAt(i) != s.charAt(j)) {
while (++i < --j)
if (s.charAt(i) != s.charAt(j))
return isPalindrome(s, i, j - 1) || isPalindrome(s, i + 1, j);
}
}
return true;
}
private boolean isPalindrome(String s, int i, int j) {
while (i < j) {
if (s.charAt(i++) != s.charAt(j--)) {
while (i < j)
if (s.charAt(i++) != s.charAt(j--))
return false;
}
}
return true;
}
```
@ -743,13 +747,18 @@ Output: [1,2,2,3,5,6]
```java
public void merge(int[] nums1, int m, int[] nums2, int n) {
int i = m - 1, j = n - 1; // 需要从尾开始遍历，否则在 nums1 上归并得到的值会覆盖还未进行归并比较的值
// 需要从尾开始遍历，否则在 nums1 上归并得到的值会覆盖还未进行归并比较的值
int i = m - 1, j = n - 1;
int index = m + n - 1;
while (i >= 0 || j >= 0) {
if (i < 0) nums1[index] = nums2[j--];
else if (j < 0) nums1[index] = nums1[i--];
else if (nums1[i] > nums2[j]) nums1[index] = nums1[i--];
else nums1[index] = nums2[j--];
if (i < 0)
nums1[index] = nums2[j--];
else if (j < 0)
nums1[index] = nums1[i--];
else if (nums1[i] > nums2[j])
nums1[index] = nums1[i--];
else
nums1[index] = nums2[j--];
index--;
}
}
@ -763,10 +772,12 @@ public void merge(int[] nums1, int m, int[] nums2, int n) {
```java
public boolean hasCycle(ListNode head) {
if (head == null) return false;
if (head == null)
return false;
ListNode l1 = head, l2 = head.next;
while (l1 != null && l2 != null && l2.next != null) {
if (l1 == l2) return true;
if (l1 == l2)
return true;
l1 = l1.next;
l2 = l2.next.next;
}
@ -793,22 +804,19 @@ public String findLongestWord(String s, List<String> d) {
String longestWord = "";
for (String target : d) {
int l1 = longestWord.length(), l2 = target.length();
if (l1 > l2 || (l1 == l2 && longestWord.compareTo(target) < 0)) {
if (l1 > l2 || (l1 == l2 && longestWord.compareTo(target) < 0))
continue;
}
if (isValid(s, target)) {
if (isValid(s, target))
longestWord = target;
}
}
return longestWord;
}
private boolean isValid(String s, String target) {
int i = 0, j = 0;
while (i < s.length() && j < target.length()) {
if (s.charAt(i) == target.charAt(j)) {
if (s.charAt(i) == target.charAt(j))
j++;
}
i++;
}
return j == target.length();