122. Best Time to Buy and Sell Stock II

class Solution {
    public int maxProfit(int[] prices) {
        int profit = 0;
        for (int i = 0; i < prices.length-1; i++){
            if(prices[i+1] > prices[i]) profit+= (prices[i+1] - prices[i]);
        }
        return profit;
    }
}

11. Container With Most Water

class Solution {
    public int maxArea(int[] height) {
        int maxArea =  Integer.MIN_VALUE;
        int l = 0;
        int r = height.length - 1;
        while(l < r){
            maxArea = Integer.max(maxArea, Integer.min(height[l],height[r])*(r-l));
            if(height[l] < height[r]) l++;
                else r--;
        }
        return maxArea;
    }
}

62. Unique Paths

Dynamic Programming

class Solution {
    public int uniquePaths(int m, int n) {
        if(n ==1 && m ==1) return 1;
        int[][] grid = new int[m][n];

        for(int i = 1;  i <m; i++){
         grid[i][0] = 1;  
        }
    
        for(int i = 1; i < n; i++){
            grid[0][i] = 1;
        }
        for(int i = 1; i < m; i++){
            for(int j = 1; j < n; j++){
                grid[i][j] =grid[i-1][j] + grid[i][j-1];
            }
        }
        return grid[m-1][n-1];
    }
}

605. Can Place Flowers

class Solution {
    public boolean canPlaceFlowers(int[] flowerbed, int n) {
        if(flowerbed.length == 1 && flowerbed[0] == 0) n--;
        for(int i = 0; i < flowerbed.length; i++){
            if(i ==0 && flowerbed[i] == 0 && i+1 <  flowerbed.length && flowerbed[i+1] == 0){
                flowerbed[i] = 1;
                n--;
            }else if( i == flowerbed.length -1 && 
                     flowerbed[i] == 0 && i-1 >= 0 &&
                     flowerbed[i-1] == 0){
            flowerbed[i] = 1;
                n--;
            }
            else if(flowerbed[i] == 0  &&
                    i-1 >= 0 &&
                    flowerbed[i-1] == 0  &&
                    i+1 <  flowerbed.length &&
                    flowerbed[i+1] == 0){
                flowerbed[i] = 1;
                n--;
            } 
        }
        if(n <= 0) return true;
        else return false;
    }
}