128 lines
3.2 KiB
C++
128 lines
3.2 KiB
C++
#include <algorithm>
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#include <cctype>
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#include <cstdint>
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#include <iostream>
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#include <istream>
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#include <limits>
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#include <string>
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#include <tuple>
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#include <utility>
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#include <vector>
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using ll = int64_t;
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ll n;
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std::string s1,s2;
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std::vector<std::vector<std::pair<ll, ll>>> dp;
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/*
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dp[k][i]=tuple(ll w,ll jt)
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k从右往左第k个字符
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i减少增加
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w消耗的次数
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jt 0不变，1进位，-1退位
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*/
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std::tuple<ll,ll> rw(ll i){
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ll ans{};
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ll jt{};
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char c = s1[i];
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while(c!=s2[i]){
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ans++;
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if(c=='z'){
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jt=1;
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c='a';
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continue;
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}
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c++;
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}
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return {ans,jt};
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}
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std::tuple<ll,ll> lw(ll i){
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ll ans{};
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ll jt{};
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char c = s1[i];
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while(c!=s2[i]){
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ans++;
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if(c=='a'){
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jt=-1;
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c='z';
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continue;
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}
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c--;
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}
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return {ans,jt};
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}
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ll setr(char &c){
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ll jt{};
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if(c=='z'){
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c='a';
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jt=1;
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}else{
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c=c+1;
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}
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return jt;
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}
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ll setl(char &c){
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ll jt{};
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if(c=='a'){
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jt=-1;
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c='z';
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}else{
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c=c-1;
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}
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return jt;
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}
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int main(){
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std::iostream::sync_with_stdio(false);
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std::cin.tie(nullptr);
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std::cout.tie(nullptr);
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std::cin>>n>>s1>>s2;
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s1=' '+s1;
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s2=' '+s2;
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dp.resize(s1.size()+1,std::vector<std::pair<ll, ll>>(2,std::pair<ll, ll>(std::numeric_limits<ll>::max(),0)));
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dp[s1.size()][0].first = dp[s1.size()][1].first = 0;
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for(ll k=s1.size()-1;k>=1;k--){
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ll nw{};
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if(isupper(s1[k]) != isupper(s2[k])){
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nw++;
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}
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s1[k]=tolower(s1[k]);
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s2[k]=tolower(s2[k]);
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for(ll i=0;i<(ll)dp[k+1].size();i++){
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if(dp[k+1][i].second==1){
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ll jt = setr(s1[k]);
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auto[tlw,tljt] = lw(k);
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auto[trw,trjt] = rw(k);
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dp[k][0].first=std::min(dp[k][0].first,tlw+dp[k+1][i].first+nw);
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if(dp[k][0].first==tlw+dp[k+1][i].first+nw)dp[k][0].second=tljt+jt;
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dp[k][1].first=std::min(dp[k][1].first,trw+dp[k+1][i].first+nw);
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if(dp[k][1].first==trw+dp[k+1][i].first+nw)dp[k][1].second=trjt+jt;
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setl(s1[k]);
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}else if(dp[k+1][i].second==-1){
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ll jt = setl(s1[k]);
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auto[tlw,tljt] = lw(k);
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auto[trw,trjt] = rw(k);
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dp[k][0].first=std::min(dp[k][0].first,tlw+dp[k+1][i].first+nw);
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if(dp[k][0].first==tlw+dp[k+1][i].first+nw)dp[k][0].second=tljt+jt;
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dp[k][1].first=std::min(dp[k][1].first,trw+dp[k+1][i].first+nw);
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if(dp[k][1].first==trw+dp[k+1][i].first+nw)dp[k][1].second=trjt+jt;
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setr(s1[k]);
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}else{
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auto[tlw,tljt] = lw(k);
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auto[trw,trjt] = rw(k);
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dp[k][0].first=std::min(dp[k][0].first,tlw+dp[k+1][i].first+nw);
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if(dp[k][0].first==tlw+dp[k+1][i].first+nw)dp[k][0].second=tljt;
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dp[k][1].first=std::min(dp[k][1].first,trw+dp[k+1][i].first+nw);
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if(dp[k][1].first==trw+dp[k+1][i].first+nw)dp[k][1].second=trjt;
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}
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}
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}
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std::cout<<std::min(dp[1][0].first,dp[1][1].first)<<'\n';
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} |