day3

[0209长度最小的子数组]

class Solution {
    public int minSubArrayLen(int target, int[] nums) {
        int numsLength = nums.length;
        for (int k = 0; k <= numsLength-1; k++){
            int sum = 0;
            int i = 0;
            int j = i + k;
            while (j <= numsLength-1){
                for(int temp = i; temp <= j; temp++){
                    sum = sum + nums[temp];
                }      
                if (sum >= target)
                    return k+1; 
                i++;
                j++;
            }
        }
        return 0;
    }
}

• 确实看到提示说是用滑动窗口代替两个for循环，但调节滑动窗口的起始位置这部分精髓代码比较蒙''''''''''

class Solution {
    public int minSubArrayLen(int target, int[] nums) {
        int numsLength = nums.length; 
        int i = 0; 
        int sum = 0;
        for (int j = 0; j <= numsLength-1; j++){
            sum += nums[j] 
            if (sum >= target){
                i ++;
                sum = sum - nums[i-1];  
            }
        }        
        }
        return 0;
    }
}

• 窗口可能大小subLength，窗口实际大小result，都还没定义出来

class Solution {
    public int minSubArrayLen(int target, int[] nums) {
        int numsLength = nums.length; 
        int result = Integer.MAX_VALUE;
        int subLength = 0;
        int i = 0; 
        int sum = 0;
        for (int j = 0; j <= numsLength-1; j++){
            sum += nums[j]; 
            while (sum >= target){                
                subLength = ( j - i + 1 );
            result = result < subLength ? result : subLength;
            sum = sum - nums[i];  
            i ++;
        }
    }        
    return result == Integer.MAX_VALUE ? 0 : result;
}
}