[数据结构与算法]数据结构数组学习

//704.二分查找
class Solution {
public:
    int search(vector<int>& nums, int target) {
        int left=0;
        int right=nums.size()-1;
        while(left<=right){
          int mediu=left+(right-left)/2;
          if(nums[mediu]==target){
               return mediu;
           }
          if(nums[mediu]<target){
              left=mediu+1;
           }
           else if(nums[mediu]>target){
              right=mediu-1;
           }
        }
        return -1;
    }
};

//27.移除元素
class Solution {
public:
    int removeElement(vector<int>& nums, int val) {
        //双指针法
        int slowidx=0;
        for(int fastidx=0;fastidx<nums.size();fastidx++){
            if(nums[fastidx]!=val){
                nums[slowidx++]=nums[fastidx];
            }
        }
        return slowidx;
    }
};

//209长度最小的子数组
  class Solution {//暴力解法
public:
    int minSubArrayLen(int target, vector<int>& nums) {
        int result=INT_MAX;
        int length;
        for(int i=0;i<nums.size();i++){
             int sum=0;
            for(int j=i;j<nums.size();j++){
                sum+=nums[j];
                if(sum>=target){
                    length=j-i+1;
                    result=(result>length)?length:result;
                      break;
                }
            }
        }
        return result==INT_MAX?0:result;

    }
};
//滑动窗口
class Solution {
public:
    int minSubArrayLen(int target, vector<int>& nums) {
        int result=INT_MAX;
        int length;
        int i=0;//起始位置
        int sum=0;
        for(int j=0;j<nums.size();j++){
                sum+=nums[j];
                while(sum>=target){
                    length=j-i+1;
                    result=(result>length)?length:result;
                    sum-=nums[i++];
                }
        }
        return result==INT_MAX?0:result;
    }
};