递归解法

class Solution {
public:
    int search(vector<int>& nums, int target) {
        return midsearch(nums,target,0,nums.size()-1);
    }
    int midsearch(vector<int>& nums, int target, int low,int high)
    {
        if(low <= high)
        {
            int mid = (low+high) / 2;
            if(nums[mid]<target) return midsearch(nums,target,mid+1,high);
            if(nums[mid]>target) return midsearch(nums,target,low,mid-1);
            if(nums[mid] == target) return mid;
        }
        return -1;
      
    }
};

class Solution {
public:
    int search(vector<int>& nums, int target) {
        int low = 0;
        int high = nums.size()-1;
        while(low<=high)
        {
            int mid = (low+high) / 2;
            if(nums[mid] == target) return mid;
            else if(nums[mid] > target) high = mid - 1;
            else low = mid + 1;
        }
        return -1;
    }
};

class Solution {
public:
    bool isAnagram(string s, string t) {
        int n1 = s.size();
        int n2 = t.size();
        if(n1!=n2) return false;
        quicksort(s,0,n1-1);
        quicksort(t,0,n2-1);
        if(s==t) return true;
        return false;
    }
    int partition(string &s ,int low,int high)
    {
        char c = s[low];
        while(low<high)
        {
            while(low<high && s[high] >= c) high--;
            s[low] = s[high];
            while(low<high && s[low] <= c) low++;
            s[high] = s[low];
        }
        s[low] = c;
        return low;
    }
    void quicksort(string &s,int low,int high)
    {
        if(low < high)
        {
            int p = partition(s,low,high);
            quicksort(s,low,p-1);
            quicksort(s,p+1,high);
        }
    }
};

顺便练习一下快排