85 lines
2.3 KiB
C++
85 lines
2.3 KiB
C++
#define NDEBUG
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#include <cstring>
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#include <fstream>
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#include <iostream>
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#include <algorithm>
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#include <limits>
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#define NV(v)#v<<" : "<<(v)
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#ifdef NDEBUG
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#define DEBUG(code)
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#else
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#define DEBUG(code){code}
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#endif
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using ll = long long;
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#ifdef NDEBUG
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auto &is = std::cin;
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#else
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auto is = std::ifstream("/root/dev/cpp/algorithm_2024/src/P3957/P3957_9.in");
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#endif
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auto &os = std::cout;
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const ll max_n = 5e5+5, ll_min{std::numeric_limits<decltype(ll_min)>::min()},
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ll_max{std::numeric_limits<decltype(ll_max)>::max()};
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ll n, d, k;
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struct Point{
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ll posit,score;
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}points[max_n];
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ll dp[max_n];
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void flush_exit(){
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os<<std::flush;
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_Exit(0);
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}
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bool check(const ll coin){
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for(ll i{0};i<max_n;i++)dp[i]=ll_min;
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dp[0]=0; // 注意第0个点是能到达的reachable
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const ll max_step {coin+d}, min_step {std::max((ll)1,d-coin)};
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for(ll i{1};i<=n;++i){
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for(ll from{i-1};from>=0;from--){
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ll dis{points[i].posit-points[from].posit};
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if(min_step<=dis){
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if(dis<=max_step){
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if(dp[from]==ll_min)continue;
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dp[i] = std::max(dp[i],dp[from]+points[i].score);
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if(dp[i]>=k){
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return true;
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}
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}else{
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break;
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}
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}
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}
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}
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return false;
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}
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int main(){
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is>>n>>d>>k;
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for(ll i{1};i<=n;++i){
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is>>points[i].posit>>points[i].score;
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}
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// const ll max_coin{(ll)1e9+5};//d+g = x[n] -> g = x[n]-d我的推导是这样的，但是错了，必须将max_coin设置为1e5+5也就是s[i]最大值，会TLE最终研究了一下应该是作者卡时间
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const ll max_coin{std::min(std::max(d-1,points[n].posit-d),(ll)1e4)};//d+g = x[n] -> g = x[n]-d我的推导是这样的，但是错了，必须将max_coin设置为1e5+5也就是s[i]最大值，会TLE最终研究了一下应该是作者卡时间
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ll l{0},r{max_coin},ans{ll_max};
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while(l<=r){
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ll mid{(l+r)/2};
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const bool check_ret{check(mid)};
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if(check_ret){
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ans = mid;
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r=mid-1;
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}else{
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l=mid+1;
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}
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DEBUG(
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os<<NV(l)<<"\t"<<NV(r)<<'\n';
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)
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}
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os<<(ans==ll_max?-1:ans)<<'\n';
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}
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