noip2015 day1

---

　　不解释，很简单，直接按照题目的方法构造就行了

Code

 #include<iostream>
 #include<cstdio>
 #include<cctype>
 #include<cstring>
 #include<map>
 #include<set>
 #include<queue>
 #include<vector>
 #include<algorithm>
 using namespace std;
 typedef bool boolean;
 template<typename T>
 inline void readInteger(T& u){
     char x;
     while(!isdigit((x = getchar())));
     for(u = x - ''; isdigit((x = getchar())); u = (u << ) + (u << ) + x - '');
     ungetc(x, stdin);
 }
 
 template<typename T>class Matrix{
     public:
         T* p;
         int width;
         int height;
         Matrix():width(), height(){}
         Matrix(int width, int height):width(width), height(height){
             p = new T[width * height];
         }
         T* operator [](int pos){
             return p + pos * width;
         }
 };
 
 int n;
 Matrix<int>    hf;
 int lx, ly;
 
 inline void init(){
     readInteger(n);
     hf = Matrix<int>(n + , n + );
 }
 
 inline void solve(){
     memset(hf.p, , sizeof(int) * (n + ) * (n + ));
     hf[][n /  + ] = ;
     lx = , ly = n /  + ;
     for(int k = ; k <= n * n; k++){
         if(lx ==  && ly != n){
             lx = n;
             ly++;
         }else if(ly == n && lx != ){
             ly = ;
             lx--;
         }else if(ly == n && lx == ){
             lx++;
         }else if(hf[lx - ][ly + ] == ){
             lx--;
             ly++;
         }else{
             lx++;
         }
         hf[lx][ly] = k;
     }
     for(int i = ; i <= n; i++){
         for(int j = ; j <= n; j++){
             printf("%d ", hf[i][j]);
         }
         putchar('\n');
     }
 }
 
 int main(){
     freopen("magic.in", "r", stdin);
     freopen("magic.out", "w", stdout);
     init();
     solve();
     return ;
 }

---

---

　　直接Tarjan，当然也可以直接用深搜（貌似要比Tarjan快一点，其实思路还是差不多的）

Code(Tarjan)

 #include<iostream>
 #include<cstdio>
 #include<cctype>
 #include<cstring>
 #include<map>
 #include<set>
 #include<stack>
 #include<queue>
 #include<vector>
 #include<algorithm>
 using namespace std;
 typedef bool boolean;
 template<typename T>
 inline void readInteger(T& u){
     char x;
     while(!isdigit((x = getchar())));
     for(u = x - ''; isdigit((x = getchar())); u = (u << ) + (u << ) + x - '');
     ungetc(x, stdin);
 }
 #define smin(a, b) a = min(a, b)
 
 typedef class Edge{
     public:
         int next;
         int end;
         Edge(const int next = , const int end = ):next(next), end(end){}
 }Edge;
 
 typedef class MapManager{
     public:
         int *h;
         Edge *edge;
         int ce;
         MapManager():h(NULL), edge(NULL), ce(){}
         MapManager(int points, int edges):ce(){
             h = new int[(const int)(points + )];
             edge = new Edge[(const int)(edges + )];
             memset(h, , sizeof(int) * (points + ));
         }
         inline void addEdge(int from, int end){
             edge[++ce] = Edge(h[from], end);
             h[from] = ce;
         }
 }MapManager;
 
 #define m_begin(g, i) (g).h[(i)]
 #define m_next(g, i) (g).edge[(i)].next
 #define m_end(g, i)    (g).edge[(i)].end
 
 int *uf;
 int cn;
 stack<int> s;
 int *visitID;
 int *exitID;
 boolean* visited;
 boolean* inStack;
 MapManager g;
 int result;
 
 inline void getSonMap(int end){
     int counter = ;
     int buf = s.top();
     int first = buf;
     s.pop();
     inStack[buf] = false;
     while(buf != end){
         buf = s.top();
         s.pop();
         inStack[buf] = false;
         uf[buf] = first;
         counter++;
     }
     if(counter > )
         smin(result, counter);
 }
 
 void Tarjan(int node){
     visitID[node] = exitID[node] = ++cn;
     visited[node] = true;
     inStack[node] = true;
     s.push(node);
     for(int i = m_begin(g, node); i != ; i = m_next(g, i)){
         int& e = m_end(g, i);
         if(!visited[e]){
             Tarjan(e);
             exitID[node] = min(exitID[node], exitID[e]);
         }else if(inStack[e]){
             exitID[node] = min(exitID[node], visitID[e]);
         }
     }
     if(exitID[node] == visitID[node]){
         getSonMap(node);
     }
 }
 
 int n;
 
 inline void init(){
     readInteger(n);
     g = MapManager(n, n);
     uf = new int[(const int)(n + )];
     visitID = new int[(const int)(n + )];
     exitID = new int[(const int)(n + )];
     inStack = new boolean[(const int)(n + )];
     visited = new boolean[(const int)(n + )];
     memset(visited, false, sizeof(boolean) * (n + ));
     memset(inStack, false, sizeof(boolean) * (n + ));
     for(int i = , a; i <= n; i++){
         readInteger(a);
         uf[i] = i;
         g.addEdge(i, a);
     }
 }
 
 inline void solve(){
     result = 0xfffffff;
     for(int i = ; i <= n; i++)
         if(!visited[i])
             Tarjan(i);
     delete[] visitID;
     delete[] exitID;
     printf("%d", result);
 }
 
 int main(){
     freopen("message.in", "r", stdin);
     freopen("message.out", "w", stdout);
     init();
     solve();
     return ;
 }

Tarjan

　　dfs的话就记一个访问的时间戳，还要即一个是否在栈中，当时间戳不为初值并且在栈中才说明是环

Code(Dfs)

#include<iostream>
#include<cstdio>
#include<cctype>
#include<cstring>
#define smin(a, b) a = min(a, b)
using namespace std;
typedef bool boolean;
template<typename T>
inline void readInteger(T& u){
    char x;
    while(!isdigit((x = getchar())));
    for(u = x - ''; isdigit((x = getchar())); u = (u << ) + (u << ) + x - '');
    ungetc(x, stdin);
}
int n;
int timec;
int* next;
int* rank;
boolean* inStack;
int result = 0xfffffff;
void find(int node){
    if(rank[node] != - && inStack[node]){
        smin(result, ++timec - rank[node]);
        return;
    }
    if(rank[node] != - )    return;
    inStack[node] = true;
    rank[node] = ++timec;
    find(next[node]);
    inStack[node] = false;
}
int main(){
    freopen("message.in", "r", stdin);
    freopen("message.out", "w", stdout);
    readInteger(n);
    next = new int[(const int)(n + )];
    rank = new int[(const int)(n + )];
    inStack = new boolean[(const int)(n + )];
    memset(rank, -, sizeof(int) * (n + ));
    for(int i = ; i <= n; i++){
        readInteger(next[i]);
        inStack[i] = false;
    }
    for(int i = ; i <= n; i++){
        if(rank[i] == -)
            find(i);
    }
    printf("%d", result);
    return ;
}

Dfs

---

---

　　思路很简单，搜！不过如果对子、三带一都去搜的话很耗时间，也很耗代码，而且它们是可以直接算出来的

稍微贪一下心，把能带走的都带走，而且从多的开始带。但是双王要记住特殊处理

　　搜的内容就只包括顺子，只不过注意所有情况都要搜到，因为某些数据顺子即使搜得长，并不是最优的，反

而导致单牌过多。其他都还是没有什么特别坑的细节。

Code

 #include<iostream>
 #include<cstdio>
 #include<cctype>
 #include<cstring>
 #include<map>
 #include<set>
 #include<queue>
 #include<vector>
 #include<algorithm>
 #define smin(a, b) a = min(a, b)
 using namespace std;
 typedef bool boolean;
 template<typename T>
 inline void readInteger(T& u){
     char x;
     while(!isdigit((x = getchar())));
     for(u = x - ''; isdigit((x = getchar())); u = (u << ) + (u << ) + x - '');
     ungetc(x, stdin);
 }
 
 int n;
 int kase;
 int key[] = {, , , , , , , , , , , , , };
 int had[];
 
 inline void init(){
     memset(had, , sizeof(had));
     for(int i = , a, b; i <= n; i++){
         readInteger(a);
         readInteger(b);
         if(a == ) had[ + b]++;
         else had[key[a]]++;
     }
 }
 
 int calc(){
     int counter[] = {, , , , };
     for(int i = ; i <= ; i++){
         if(had[i] > ){
             counter[had[i]]++;
         }
     }
     int reter = ;
     boolean aFlag = ;
     if(had[] ==  && had[] == ){
         aFlag = ;
     }
     while(counter[] && counter[] >= ) reter++, counter[] -= , counter[] -= ;
     while(counter[] && counter[] >= ) reter++, counter[] -= , counter[] -= ;
     while(counter[] && counter[]) reter++, counter[] -= , counter[] -= ;
     while(counter[] && counter[])    reter++, counter[] -= , counter[] -= ;
     while(counter[] && counter[])    reter++, counter[] -= , counter[] -= ;
     if(counter[] >=  && aFlag) counter[] -= ;
     return reter + counter[] + counter[] + counter[] + counter[];
 }
 
 int result;
 void search(int last, int times){
     if(last == ){
         smin(result, times);
         return;
     }
     smin(result, times + calc());
     if(times >= result)    return;
     //顺子
     if(last >= ){
         for(int p = ; p >= ; p--){
             for(int i = ; i <= ; i++){
                 int k = i;
                 while(had[k] >= p && k < ) k++;
                 if((k - i) * p >= ){
                     for(int j = i; j < k; j++){
                         had[j] -= p;
                     }
                     for(int j = k - ; j >= i; j--){
                         if((j - i + ) * p >= )
                             search(last - (j - i + ) * p, times + );
                         had[j] += p;
                     }
                 }
             }
         }
     }
 }
 
 int main(){
     freopen("landlords.in", "r", stdin);
     freopen("landlords.out", "w", stdout);
     readInteger(kase);
     readInteger(n);
     while(kase--){
         init();
         result = n;
         search(n, );
         printf("%d\n", result);
     }
     return ;
 }