cf 556C Case of Matryoshkas

最大连续区间和是一个经典的问题。给定一个长度为 n 的序列 a[1],a[2]…a[n-1],a[n]，求一个连续的子序列 a[i],a[i+1]…a[j-1],a[j]，使得 a[i]+a[i+1]…a[j-1]+a[j]最大。

http://codeforces.com/problemset/problem/548/A 水题。分割成K个，每个串判断是否回文，如果都是就yes，否则no

B. Tavas and SaDDas time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Once again Tavas started eating coffee mix without water! Keione told him that it smells awful, but he didn’t stop doing that. That’s why Keione told his smart friend, SaDDas to punish him! SaDDas took Tavas’ headphones and told him: “If you solve the following problem, I’ll return it to you.”

http://poj.org/problem?id=3278 bfs,用到了stl的queue 1 2 3 /* *********************************************** 4 Author :111qqz 5 Created Time :2016年02月19日 星期五 15时45分05秒 6 File Name :3278.cpp 7 ************************************************ */ 8 9 #include <algorithm> 10 #include <cstdio> 11 #include <iostream> 12 #include <cstring> 13 #include <string> 14 #include <cmath> 15 #include <map> 16 #include <stack> 17 #include <queue> 18 19 using namespace std; 20 typedef long long LL; 21 const int inf = 8E8; 22 const int N=2E5+7; 23 int d[N]; 24 int n,k; 25 void bfs() 26 { 27 queue<int> q; 28 memset(d,-1,sizeof(d)); 29 q.push(n); 30 d[n]=0; 31 while (!q.empty()) 32 { 33 int x = q.front(); 34 q.pop(); 35 if ( x==k ) 36 { 37 break; 38 } 39 int next[10]; 40 next[1]=x-1; 41 next[2]=x+1; 42 next[3]=2*x; 43 for ( int i = 1; i <= 3 ; i++ ) 44 { 45 if (next[i]>=0&&next[i]<=100000&&d[next[i]]==-1) 46 { 47 d[next[i]]=d[x]+1; 48 q.push(next[i]); 49 } 50 } 51 } 52 53 54 } 55 int main() 56 { 57 while (scanf("%d %d",&n,&k)!=EOF) 58 { 59 bfs(); 60 cout<<d[k]<<endl; 61 } 62 return 0; 63 }

http://poj.org/problem?id=1028 1 2 3 4 /* *********************************************** 5 Author :111qqz 6 Created Time :2016年02月19日 星期五 15时45分01秒 7 File Name :1028.cpp 8 ************************************************ */ 9 10 #include <algorithm> 11 #include <cstdio> 12 #include <iostream> 13 #include <cstring> 14 #include <string> 15 #include <cmath> 16 #include <map> 17 #include <stack> 18 #include <queue> 19 20 using namespace std; 21 typedef long long LL; 22 const int inf = 8E8; 23 stack<string> backstack; 24 stack<string> forwardstack; 25 string cur; 26 string cmd; 27 int main() 28 { 29 cur ="http://www.acm.org/"; 30 31 while (cin>>cmd) 32 { 33 if (cmd=="QUIT") 34 { 35 break; 36 } 37 if (cmd=="BACK") 38 { 39 if (backstack.empty()) 40 { 41 cout<<"Ignored"<<endl; 42 continue; 43 } 44 forwardstack.push(cur); 45 cur=backstack.top(); 46 backstack.pop(); 47 cout<<cur<<endl; 48 } 49 if (cmd=="FORWARD") 50 { 51 if (forwardstack.empty()) 52 { 53 cout<<"Ignored"<<endl; 54 continue; 55 } 56 backstack.push(cur); 57 cur=forwardstack.top(); 58 forwardstack.pop(); 59 cout<<cur<<endl; 60 } 61 if (cmd=="VISIT") 62 { 63 backstack.push(cur); 64 65 cin>>cur; 66 while (!forwardstack.empty()) forwardstack.pop(); 67 cout<<cur<<endl; 68 69 } 70 } 71 72 73 return 0; 74 }