代码随想录第二天|209.长度最小的子数组(滑动窗口)

209.长度最小的子数组

class Solution {
    public int minSubArrayLen(int target, int[] nums) {
        int left = 0;
        int sum = 0;
        //int result = Integer.MAX_VALUE;无法编译，改成长度+1
        int result = nums.length + 1;
        for(int right = 0; right < nums.length; right++){
            sum += nums[right];
            while(sum >= target){
                result = Math.min(result, right - left +1);
                sum -= nums[left++];
            }
        }
        return result == nums.length + 1 ? 0 : result;
    }
}

 

 59.螺旋矩阵II

 

class Solution {
    public int[][] generateMatrix(int n) {
        int[][] nums = new int[n][n];
        //start piont every loop;
        int startX = 0;
        int startY = 0;
        //set num every loop;
        int flag = 1;
        //fill the maxtrix;
        int count = 1;
        //count loop number;
        int loop = 1;
        int i, j;

        while(loop <= n/2){
            //the top row
            for(j = startY; j < n - flag; j++){
                nums[startX][j] = count++;
            }
            //right column
            for(i = startX; i < n - flag; i++){
                nums[i][j] = count++;
            }
            //bottom row
            for(;j > startY; j--){
                nums[i][j] = count++;
            }
            //left column
            for(; i > startX; i--){
                nums[i][j] = count++;
            }
            startX++;
            startY++;
            flag++;
            loop++;
        }

        if(n % 2 == 1){
            nums[startX][startY] = count;
        }
        return nums;
    }
}

 

区间和 以后看

总结：