Day 12

1.删除公共字符 (pass)

删除公共字符
哈希、字符串、枚举

1.1 解析

1.2 代码

#include <iostream>
#include <unordered_set>
using namespace std;
int main()
{string s1,s2;getline(cin,s1);getline(cin,s2);//将第二个字符串存放hash// unordered_set<char> hash;// for(auto& e:s2)//     hash.insert(e);bool hash[300]={0};for(char ch:s2) hash[ch]=true;string tmp;int n=s1.size();for(int i=0;i<n;i++){// if(!hash.count(s1[i]))//     tmp+=s1[i];if(!hash[s1[i]]) tmp+=s1[i];}cout<<tmp;return 0;
}

2.两个链表的第一个公共结点 (pass)

两个链表的第一个公共结点
链表

2.1 解析

2.2 代码

/*
struct ListNode {int val;struct ListNode *next;ListNode(int x) :val(x), next(NULL) {}
};*/
class Solution {
public:ListNode* FindFirstCommonNode( ListNode* head1, ListNode* head2) {//1.统计2个链表的长度int len1=0,len2=0;ListNode* cur=head1;while(cur){len1++;cur=cur->next;}cur=head2;while(cur){len2++;cur=cur->next;}//2.让长的链表先走ListNode* maxhead=head1,*minhead=head2;if(len2>len1){maxhead=head2;minhead=head1;}int tmplen=abs(len1-len2);while(tmplen--){maxhead=maxhead->next;}//3.让2个链表一起走while(maxhead!=minhead){maxhead=maxhead->next;minhead=minhead->next;}return maxhead;}
};

3. mari和shiny

mari和shiny
多状态线性dp

3.1 解析

3.2 代码

#include <iostream>
#include <vector>
using namespace std;
int main()
{long long s=0,h=0,y=0;int n=0;cin>>n;string str;cin>>str;//初始化s=str[0]=='s'?1:0;//2.填表for(int i=1;i<n;i++){if(str[i]=='s')s++;else if(str[i]=='h') h+=s;else if(str[i]=='y') y+=h;}cout<<y;return 0;
}
/*int main()
{int n=0;cin>>n;string str;cin>>str;//1.创建dp表vector<long long> s(n);vector<long long> h(n);vector<long long> y(n);//2.初始化s[0]=str[0]=='s'?1:0;//3.填表for(int i=1;i<n;i++){s[i]=str[i]=='s'?s[i-1]+1:s[i-1];h[i]=str[i]=='h'?s[i-1]+h[i-1]:h[i-1];y[i]=str[i]=='y'?h[i-1]+y[i-1]:y[i-1];}cout<<y[n-1];return 0;
}*/