#include<bits/stdc++.h>#include<math.h>#include<map>#include<queue>#include<stack>#include<assert.h>#include <algorithm>#define ll long long#define mod 1000000007usingnamespacestd;chars[100005];intlen;typedefunsigned longlongull;ull hashed[100005];ull phashed[100005];ull seed = 19260817;ull power[100005];ull get(inti,intj){if(j<i)return0;returnhashed[j] - hashed[i-1]*power[j-i+1];}ull pget(inti,intj){if(j<i)return0;returnphashed[i] - phashed[j+1]*power[j-i+1];}boolcheck(inti,charj){i+=1;if(len%2==0){intmid = (len+1)/2;if(i==mid+1){ull l = get(1,mid);ull r = pget(mid+1,len);if(l==r)returntrue;}elseif(i<mid+1){ull r = pget(mid+1,len);ull l;l = get(1,i-1);l = l*seed + ((j-'0') + 1);l = l*power[mid-i] + get(i,mid-1);if(l==r)returntrue;}else{ull l = get(1,mid);ull r;r = pget(i,len);r = r*seed + ((j-'0')+1);// if(i==5&&j=='j'){// cout<<get(1,1)<<" "<<r<<" "<<len<<" "<<mid+2<<" "<<i-1<<" "<<p<<endl;// }r = r*power[i-2-mid] + pget(mid+2,i-1);if(l==r)returntrue;}}else{// cout<<"OK"<<endl;intmid = (len+1)/2;if(i<mid){ull r = pget(mid,len);ull l;l = get(1,i-1);l = l*seed + ((j-'0') + 1);l = l*power[mid-i] + get(i,mid-1);//cout<<l<<" "<<r<<" "<<i<<" "<<mid<<endl;;if(l==r)returntrue;}else{ull l = get(1,mid);ull r;r = pget(i,len);r = r*seed + ((j-'0')+1);r = r*power[i- 1 - mid] + pget(mid+1,i-1);if(l==r)returntrue;}}returnfalse;}voidinit(){power[0] = 1;hashed[0] = 0;for(inti=1;i<=len;++i)power[i] = power[i-1] * seed;for(inti=1;i<=len;++i)hashed[i] = hashed[i-1]*seed + (s[i]-'0') + 1;phashed[len+1] = 0;for(inti=len;i>=1;--i)phashed[i] = phashed[i+1]*seed + (s[i]-'0') + 1;}intmain(){scanf("%s",s+1);len = strlen(s+1);init();for(inti=0;i<=len;i++){for(charj='a';j<='z';++j){if(check(i,j)){printf("Yes");// cout<<i<<" "<<j<<endl;exit(0);}}for(charj='A';j<='Z';++j){if(check(i,j)){printf("Yes");// cout<<i<<" "<<j<<endl;exit(0);}}for(charj='0';j<='9';++j){if(check(i,j)){printf("Yes");// cout<<i<<" "<<j<<endl;exit(0);}}}printf("No");exit(0);return0;}
身旁的大佬取完快递闲着无聊,字符串hash+前缀和+后缀和解决本题。。。。。
自己想的dfs递归的时候写成st++,ed--,错了。
心里好难过的说。
特此留念
太惨了
唉。
嗯 就这样 滚去刷下一道题
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