day13

1.剑指 Offer 21. 调整数组顺序使奇数位于偶数前面

class Solution {
public:
    vector<int> exchange(vector<int>& nums) {
      int n = nums.size();
      int l = 0,r = n - 1;
      while(l < r){
          if(nums[l] % 2 == 0 && nums[r] % 2 != 0){
              swap(nums[l],nums[r]);
              l ++;
              r --;
          }
          if(nums[l] % 2 != 0)
           l ++;
          if(nums[r] % 2 == 0)
           r --;
      }
      return nums;
    }
};

2.剑指 Offer 57. 和为 s 的两个数字

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
      vector<int> res;
      int n = nums.size();
      int i = 0,j = n - 1;
      while(i < j){
        if(nums[i] + nums[j] == target)  break;
        else if(nums[i] + nums[j] > target) j --;
        else i ++;
      }
      res.push_back(nums[i]);
      res.push_back(nums[j]);
      return res;
    }
};

还可用二分法