4.28LeetCode

class Solution {
public:
    string countAndSay(int n) {
        string res="1";
        for(int i=1;i<n;i++)
            res=next(res);
        return res;
    }
    string next(string n) {
        int i=0;
        string res;
        while(i<n.length()){
            char temp=n[i];
            int num=1;
            while(1){
                if(i+1!=n.length()&&n[i+1]==n[i])
                {
                    num++; 
                    i++;
                }
                else break;
            }
            res+=to_string(num);
            res+=temp;
            i++;
        }
        return res;
    }
};

class Solution {
public:
    void deleteNode(ListNode* node) {
        ListNode* p=node;
        while(p->next){
            p->val=p->next->val;
            p=p->next;
        } 
        while(node->next!=p)
            node=node->next;
        node->next=nullptr;
        return;
    }
};

class Solution {
public:
    void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
        int i=0,j=0;
        vector<int> temp;
        while(i<m&&j<n){
            if(nums1[i]<=nums2[j])
            {
                temp.push_back(nums1[i]);
                i++;
            }else{
                temp.push_back(nums2[j]);
                j++;
            }
        }
        if(i!=m){
            while(i!=m){
                temp.push_back(nums1[i]);
                i++;               
            }
        }
        if(j!=n){
            while(j!=n){
                temp.push_back(nums2[j]);
                j++;                
            }
        }
        i=0;
        for(int it:temp){
            nums1[i]=it;
            i++;
        }
        return;
    }
};

class Solution {
public:
    int climbStairs(int n) {
        if(n==1) return 1;
        vector<int> dp;
        dp.resize(n);
        dp[0]=1;dp[1]=2;
        for(int i=2;i<n;i++)
            dp[i]=dp[i-1]+dp[i-2];
        return dp[n-1];
    }
};

class Solution {
public:
    int maxSubArray(vector<int>& nums) {
        int tempmax,res;
        res=nums[0];
        tempmax=0;
        for(int i=0;i<nums.size();i++){
            tempmax=max(tempmax+nums[i],nums[i]);
            res=max(res,tempmax);
        }
        return res;
    }
};