[pull] master from youngyangyang04:master #69

Original file line number	Diff line number	Diff line change
Expand Up		@@ -263,21 +263,38 @@ public:
		Java:

		```java
	public int[] twoSum(int[] nums, int target) {
	int[] res = new int[2];
	if(nums == null \|\| nums.length == 0){
	return res;
	}
	Map<Integer, Integer> map = new HashMap<>();
	for(int i = 0; i < nums.length; i++){
	int temp = target - nums[i];
	if(map.containsKey(temp)){
	res[1] = i;
	res[0] = map.get(temp);
	// 双指针动态规划
	class Solution {
	public String longestPalindrome(String s) {
	if (s.length() == 0 \|\| s.length() == 1) return s;
	int length = 1;
	int index = 0;
	boolean[][] palindrome = new boolean[s.length()][s.length()];
	for (int i = 0; i < s.length(); i++) {
	palindrome[i][i] = true;
	}

	for (int L = 2; L <= s.length(); L++) {
	for (int i = 0; i < s.length(); i++) {
	int j = i + L - 1;
	if (j >= s.length()) break;
	if (s.charAt(i) != s.charAt(j)) {
	palindrome[i][j] = false;
	} else {
	if (j - i < 3) {
	palindrome[i][j] = true;
	} else {
	palindrome[i][j] = palindrome[i + 1][j - 1];
	}
	}
	if (palindrome[i][j] && j - i + 1 > length) {
	length = j - i + 1;
	index = i;
	}
	}
		}
	map.put(nums[i], i);
	return s.substring(index, index + length);
		}
	return res;
		}
		```

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21 changes: 21 additions & 0 deletions problems/0463.岛屿的周长.md

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Original file line number	Diff line number	Diff line change
Expand Up		@@ -118,6 +118,27 @@ class Solution {
		return res;
		}
		}

	// 解法二
	class Solution {
	public int islandPerimeter(int[][] grid) {
	// 计算岛屿的周长
	// 方法二 : 遇到相邻的陆地总周长就-2
	int landSum = 0; // 陆地数量
	int cover = 0; // 相邻陆地数量
	for (int i = 0; i < grid.length; i++) {
	for (int j = 0; j < grid[0].length; j++) {
	if (grid[i][j] == 1) {
	landSum++;
	// 统计上面和左边的相邻陆地
	if(i - 1 >= 0 && grid[i-1][j] == 1) cover++;
	if(j - 1 >= 0 && grid[i][j-1] == 1) cover++;
	}
	}
	}
	return landSum * 4 - cover * 2;
	}
	}
		```

		Python:
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