**283. 移动零（入门双指针）**

public void moveZeroes(int[] nums) {
    int n = nums.length;
    int idx = 0;
    int count = 0;
    for(int i = 0; i < n; i++) {
        if(nums[i] == 0) count++;
        else nums[idx++] = nums[i];
    }
    for(int i = n - count; i < n; i++) {
        nums[i] = 0;
    }
    return ;
}

392. 判断子序列

public boolean isSubsequence(String s, String t) {
    int sn = s.length();
    int tn = t.length();
    int si = 0, ti = 0;
    while(si < sn && ti < tn) {
        if(s.charAt(si) == t.charAt(ti)) {
            si++; ti++;
        }else {
            ti++;
        }
    }
    return si == sn;
}

11. 盛最多水的容器

public int maxArea(int[] height) {
    int l = 0, r = height.length - 1;
    int ans = 0;
    while(l < r) {
        int h = Math.min(height[l], height[r]);
        ans = Math.max(ans, (r - l) * h);
        if(height[l] >= height[r]) r--;
        else l++;
    }
    return ans;
}

1679. K 和数对的最大数目

public int maxOperations(int[] nums, int k) {
    int ans = 0;
    int l = 0, r = nums.length - 1;
    Arrays.sort(nums);
    while(l < r) {
        int sum = nums[l] + nums[r];
        if(sum > k) r--;
        else if(sum < k) l++;
        else {
            r--; l++; ans++;
        }
    }
    return ans;
}