代码随想录 day2 打卡 leetcode 209.长度最小的子数组、59.螺旋矩阵II

leetcode 209  解决方法 ：滑动窗口

class Solution 
{
public:
    int minSubArrayLen(int target, vector<int>& nums) 
    {
        int l = 0, r = 0;
        int ans = nums.size() + 1;
        int sum = 0;
        while (r < nums.size())
        {
            /*做的时候在这个地方int sum=0，出现了错误一直没发现，在循环内int sum=0
             会导致结束一次循环的时候，进行下一次循环时原有的累加数据变成初始值0 */
            sum += nums[r];
            while (sum >= target)
            {
                int len;
                len = r - l + 1;
                sum -= nums[l];
                l++;
                ans = min(ans, len);
            }
            r++;
        }
        return ans == nums.size()+1 ? 0 : ans;
    }
};

leetcode 59 螺旋矩阵 II

class Solution {
public:
    vector<vector<int>> generateMatrix(int n) {
        vector<vector<int>>vec(n, vector<int>(n, 0));
        int xi = 0, yj = 0;
        int loop = n / 2;
        int center = n / 2;
        int count = 1;
        int offset = 1;
        int i, j;
        while (loop--)
        {
            i = xi, j = yj;
            for (j; j < n - offset; j++) 
            {
                vec[i][j] = count++;
            }
            for (i; i < n - offset; i++) 
            {
                vec[i][j] = count++;
            }
            for (; j > yj; j--) 
            {
               vec[i][j] = count++;
            }
            for (; i > xi; i--) {
                vec[i][j] = count++;
            }
            xi++;
            yj++;
            offset += 1;
        }
        if (n % 2)
        {
            vec[center][center] = count;
        }
        return vec;
    }
};