代码随想录算法训练营第二天|209 长度最小的子数组、59 螺旋矩阵||

一、209 长度最小的子数组

//滑动窗口算法
int minSubArrayLen(int target, int* nums, int numsSize) {
    int i =0;//起始指针
    int result=INT_MAX;//最终结果
    int sum = 0;//总和
    for(int j=0;j<numsSize;j++){//从头开始移动终止指针
        sum += nums[j];
        while(sum>=target){//判断sum是否大于等于target
            int subLength = j-i+1;
            result = result<subLength?result:subLength;
            sum = sum - nums[i];//求出新的总和
            i++;//移动起始指针
        }
    }
    return result==INT_MAX?0:result;
}
//暴力法
int minSubArrayLen(int target, int* nums, int numsSize) {
    int sum;//总和
    int result = INT_MAX;
    for(int i=0;i<numsSize;i++){//从起始位置开始
        sum = 0;//每次开始sum都清零
        for(int j =i;j<numsSize;++j){//终止开始移动寻找符合条件的子数组
            sum +=nums[j];
            if(sum>=target){
                int subLength = j-i+1;
                result = result<subLength?result:subLength;
            }
        }
    }
    return result==INT_MAX?0:result;
}

二、59 螺旋矩阵 ||

int** generateMatrix(int n, int* returnSize, int**returnColumnSizes) {
    *returnSize = n;
    * returnColumnSizes = (int*)malloc(sizeof(int)*n);
    int** nums = (int**)malloc(sizeof(int*) * n);
    int i;
    for(i = 0; i < n; i++) {
        nums[i] = (int*)malloc(sizeof(int) * n);
        (*returnColumnSizes)[i] = n;
    }
    int startx = 0 ;//行
    int starty = 0;//列
    int offset = 1;//控制终止位置
    int count = 1;//填数
    int mid = n/2;//当n为奇数时，mid=count
    int loop = n/2;//缩短循环圈数
    while(loop){
        int i = startx;
        int j = starty;
        for(;j<starty+n-offset;j++)
            nums[startx][j] = count++;
        for(;i<startx+n-offset;i++)
            nums[i][j] = count++;
        for(;j>starty;j--)
            nums[i][j] = count++;
        for(;i>startx;i--)
            nums[i][j] = count++;
        startx++;
        starty++;
        offset+=2;
        loop--;
    }
    if(n%2)
        nums[mid][mid]=count;
    return nums;
}