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85 changes: 85 additions & 0 deletions solution/035.Search Insert Position/README.md
Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,7 @@

除此之外还可用二分法做解。


```java
class Solution {
public int searchInsert(int[] nums, int target) {
Expand Down Expand Up @@ -90,3 +91,87 @@ class Solution {
}
}
```

#### CPP

思路1:

1. 先调函数查找是否存在target元素
2. 若存在,用二分法进行查找,或者顺序遍历
3. 若不存在,则顺序遍历插入

时间复杂度O(log2(n))~O(n)

思路2:
1. 直接顺序遍历---需要点取巧,下标比nums长度小,nums[p]元素要比targat小

时间复杂度O(n)

```CPP
class Solution {
public:
int searchInsert(vector<int>& nums, int target) {
int len = nums.size();
if(len == 0){
nums.push_back(target);
return 0;
}

auto iter = find(nums.begin(),nums.end(),target);

if(iter != nums.end()){
return binarySearch(nums,0,len - 1,target);
}
else{
int slow = 0;
int fast = 1;

if(nums[0] >= target)return 0;
if(nums[len-1] <= target)return len;

while(fast < len){
if(nums[slow] <= target && nums[fast] > target){
nums.insert(nums.begin() + fast,target);
return fast;
}
else{
slow++;
fast++;
}
}
return fast;
}
}


int binarySearch(vector<int> &nums,int left,int right,int target){
if(nums[left] == target)return left;
if(nums[right] == target)return right;

int mid = (left + right) / 2;
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mid = (left + right) / 2 这个写法并不好,可能发生溢出而导致程序错误。
最好写成 mid = left + ((right - left) >> 1) 噢~


if(nums[mid] > target)return binarySearch(nums,left+1,mid,target);
else if(nums[mid] < target)return binarySearch(nums,mid,right-1,target);
else return mid;
}

};

-------------------------
class Solution {
public:
int searchInsert(vector<int>& nums, int target) {
if (nums.size() == 0) {
nums.push_back(target);
return 0;
}
unsigned int i = 0;

while(i<nums.size()&&nums[i]<target)i++;

nums.insert(nums.begin() + i, target);
return i;
}
};

```
65 changes: 65 additions & 0 deletions solution/035.Search Insert Position/Solution.cpp
Original file line number Diff line number Diff line change
@@ -0,0 +1,65 @@
class Solution {
public:
int searchInsert(vector<int>& nums, int target) {
int len = nums.size();
if(len == 0){
nums.push_back(target);
return 0;
}

auto iter = find(nums.begin(),nums.end(),target);

if(iter != nums.end()){
return binarySearch(nums,0,len - 1,target);
}
else{
int slow = 0;
int fast = 1;

if(nums[0] >= target)return 0;
if(nums[len-1] <= target)return len;

while(fast < len){
if(nums[slow] <= target && nums[fast] > target){
nums.insert(nums.begin() + fast,target);
return fast;
}
else{
slow++;
fast++;
}
}
return fast;
}
}


int binarySearch(vector<int> &nums,int left,int right,int target){
if(nums[left] == target)return left;
if(nums[right] == target)return right;

int mid = (left + right) / 2;

if(nums[mid] > target)return binarySearch(nums,left+1,mid,target);
else if(nums[mid] < target)return binarySearch(nums,mid,right-1,target);
else return mid;
}

};

-------------------------
class Solution {
public:
int searchInsert(vector<int>& nums, int target) {
if (nums.size() == 0) {
nums.push_back(target);
return 0;
}
unsigned int i = 0;

while(i<nums.size()&&nums[i]<target)i++;

nums.insert(nums.begin() + i, target);
return i;
}
};