题意见紫书
将子树映射成数字并进行编码即可
具体实现细节可能不太好想，参考lrj代码即可
#include<iostream> #include<cmath> #include<cstdio> #include<cstdlib> #include<cstring> #include<iomanip> #include<assert.h> #include<ctime> #include<vector> #include<list> #include<map> #include<set> #include<sstream> #include<stack> #include<queue> #include<string> #include<bitset> #include<algorithm> using namespace std; #define me(s) memset(s,0,sizeof(s)) #define _for(i,a,b) for(int i=(a);i<(b);++i) #define _rep(i,a,b) for(int i=(a);i<=(b);++i) #define mp make_pair #define pb push_back #define all(x) (x).begin(),(x).end() #define F first #define S second #define pf printf #define sf scanf #define Di(x) int x;scanf("%d",&x) #define in(x) inp(x) #define in2(x,y) inp(x),inp(y) #define in3(x,y,z) inp(x),inp(y),inp(z) #define ins(x) scanf("%s",x) #define ind(x) scanf("%lf",&x) #define IO ios_base::sync_with_stdio(0);cin.tie(0) #define READ freopen("C:/Users/ASUS/Desktop/in.txt","r",stdin) #define WRITE freopen("C:/Users/ASUS/Desktop/out.txt","w",stdout) template<class T> void inp(T &x) {//读入优化 char c = getchar(); x = 0; for (; (c < 48 || c>57); c = getchar()); for (; c > 47 && c < 58; c = getchar()) { x = (x << 1) + (x << 3) + c - 48; } } typedef pair <int, int> pii; typedef long long ll; typedef unsigned long long ull; const int inf = 0x3f3f3f3f; const int mod = 1e9 + 7; const double pi = acos(-1.0); const double eps = 1e-15; const int maxn=50*1e4+5; int lch[maxn],rch[maxn]; struct Node{ string s; int l,r,hash; bool operator<(const Node &rhs) const {//定义个排序准则 if(hash!=rhs.hash) return hash<rhs.hash; if(l!=rhs.l) return l<rhs.l; return r<rhs.r; } }tree[maxn]; char expr[maxn],*p; int vis[maxn]; int cnt;//分配节点 int cas; map<Node,int> dict; int build(){ int id=++cnt; Node &u=tree[id]; u.l=u.r=-1; u.s="";u.hash=0; while(isalpha(*p)){//提取节点名字 u.hash=u.hash*27+(*p)-'a'+1; u.s.pb(*p); p++; } if(*p=='('){ p++;//跳过左括号 u.l=build(); p++;//跳过逗号 u.r=build(); p++;//跳过又括号 } if(dict.count(u)!=0) { --cnt; return dict[u]; } return dict[u]=id; } void print(int rt){ if(vis[rt]==cas) printf("%d",rt); else{ vis[rt]=cas; printf("%s",tree[rt].s.c_str()); if(tree[rt].l!=-1){ putchar('('); print(tree[rt].l); putchar(','); print(tree[rt].r); putchar(')'); } } } int main(){ //READ; //WRITE; Di(T);me(vis); for(cas=1;cas<=T;cas++){ ins(expr); p=expr; cnt=0; dict.clear(); print(build()); puts(""); } }