BZOJ 2145: 悄悄话 （打表）

BZOJ 2145

题解

直接代词，所有格，常用副词，助动词，冠词，常用词打表 比较出现次数的多少来决定循环位移了几位。

CODE

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 5200;
const int p = 137;
typedef unsigned long long ULL;
map<int,bool>vis;
inline ULL hsh(const char *s) {
	ULL re = 0; int i = 0;
	while(s[i])
		re = re * p + (ULL)s[i++];
	return re;
}
inline void ins(const char *s) { vis[hsh(s)] = 1; }
inline void dictionary() {
	ins("his");
	ins("her");
	ins("is");
	ins("are");
	ins("who");
	ins("whom");
	ins("whose");
	ins("whoever");
	ins("was");
	ins("were");
	ins("i");
	ins("we");
	ins("you");
	ins("they");
	ins("them");
	ins("me");
	ins("go");
	ins("and");
	ins("no");
	ins("please");
	ins("or");
	ins("but");
	ins("so");
	ins("because");
	ins("although");
	ins("good");
	ins("bad");
	ins("well");
	ins("happy");
	ins("a");
	ins("the");
	ins("at");
	ins("i'm");
	ins("in");
	ins("on");
	ins("by");
	ins("my");
	ins("your");
	ins("rather");
	ins("than");
	ins("little");
	ins("few");
	ins("fewer");
	ins("what");
	ins("how");
	ins("when");
	ins("where");
	ins("be");
	ins("also");
	ins("make");
	ins("do");
	ins("did");
	ins("done");
	ins("up");
	ins("down");
	ins("of");
	ins("had");
	ins("has");
	ins("have");
	ins("since");
	ins("it");
	ins("its");
	ins("think");
	ins("thought");
	ins("thinking");
	ins("their");
	ins("for");
	ins("find");
	ins("with");
	ins("been");
	ins("better");
	ins("worse");
	ins("more");
	ins("less");
	ins("fine");
	ins("set");
	ins("you're");
	ins("right");
	ins("can");
	ins("could");
	ins("should");
	ins("would");
	ins("that");
	ins("this");
	ins("those");
	ins("these");
	ins("against");
	ins("back");
	ins("about");
	ins("many");
	ins("much");
	ins("as");
	ins("now");
	ins("own");
	ins("our");
	ins("from");
	ins("work");
	ins("will");
	ins("worst");
	ins("best");
	ins("never");
	ins("ever");
	ins("since");
	ins("hit");
	ins("within");
	ins("before");
	ins("after");
	ins("if");
	ins("whether");
	ins("something");
	ins("someone");
	ins("somebody");
	ins("anything");
	ins("anyone");
	ins("anybody");
	ins("nothing");
	ins("nobody");
	ins("none");
	ins("whatever");
	ins("however");
	ins("wherever");
	ins("finally");
	ins("home");
	ins("very");
	ins("quite");
	ins("an");
	ins("only");
	ins("not");
	ins("while");
	ins("off");
	ins("out");
	ins("you're");
}
char s[5005], tmp[5005];
int l[5005], r[5005];
inline char solve(char x, int k) {
	if(!isalpha(x)) return x;
	if(x >= 'A' && x <= 'Z') return 'a' + (x-'A'+k)%26;
	else return 'a' + (x-'a'+k)%26;
}
inline bool chk(char x) { return x == ' '|| x == ',' || x == '.' || x == '?' || x == '!' || x == ';' || x == '\n'; }
inline void get(char *S) {
	char ch; int i = 0;
	while((ch=getchar())=='\n');
	S[i++] = ch;
	while((ch=getchar())!='\n')S[i++]=ch;
	S[i] = 0;
}
int main () {
	dictionary();
	int T = 10;
	while(T--) {
		int cur = 0, n;
		get(s); n = strlen(s);
		for(int i = 0; i < n; ++i) {
			if(i == 0 || chk(s[i-1])) l[++cur] = i;
			if(i == n-1 || chk(s[i+1])) r[cur] = i;
		}
		for(int i = 1; i <= cur; ++i)
			if(s[r[i]] == '.' || s[r[i]] == '?' || s[r[i]] == '!' || s[r[i]] == ';' || s[r[i]] == ',') --r[i];
		int mx = 0, ans = 0;
		for(int k = 0; k <= 25; ++k) {
			int now = 0;
			for(int i = 1; i <= cur; ++i) {
				for(int j = l[i]; j <= r[i]; ++j)
					tmp[j-l[i]] = solve(s[j], k);
				tmp[r[i]-l[i]+1] = 0;
				now += vis[hsh(tmp)];
			}
			if(now > mx) mx = now, ans = k;
		}
		for(int i = 0; i < n; ++i) {
			if(!isalpha(s[i])) putchar(s[i]);
			else putchar(s[i] = (s[i] >= 'A' && s[i] <= 'Z') ? 'A' + (s[i]-'A'+ans) % 26 : 'a' + (s[i]-'a'+ans) % 26);
		}
		if(T) puts("");
	}
}