Submission #167010

#	Time	Username	Problem	Language	Result	Execution time	Memory
167010		errorgorn	JOIOJI (JOI14_joioji)	C++14	20 / 100	1072 ms	3292 KiB

joioji

#include <cstdio>
#include <unordered_map>
#include <utility>
#include <string>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <chrono>
using namespace std;
typedef pair<int,int> ii;
int n;
char c;
string s;
struct custom_hash {
    const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        return splitmix64(x + FIXED_RANDOM);
    }
    size_t operator()(const pair<int,int> &i)const{
        return splitmix64(((long long)i.first)|(((long long)i.second)<<32)+FIXED_RANDOM);
    }
};
unordered_map<ii,int,custom_hash> suffix;
int arr[3];
int pre[3];
int main(){
    suffix.reserve(4096);
    suffix.max_load_factor(0.25);
    //freopen("input.txt","r",stdin);
    scanf("%d",&n);
    getchar();
    c=getchar();
    while (c!='\n'){
        s+=c;
        if (c=='J') arr[0]++;
        else if (c=='O') arr[1]++;
        else arr[2]++;
        c=getchar();
    }
    suffix[ii(0,0)]=0;
    for (int x=0;x<3;x++) pre[x]=arr[x];
    for (int x=0;x<s.size();x++){
        if (s[x]=='J') pre[0]--;
        else if (s[x]=='O') pre[1]--;
        else pre[2]--;
        suffix[ii(pre[0]-pre[1],pre[0]-pre[2])]=x+1;
    }
    memset(pre,0,sizeof(pre));
    int ans=0;
    int a=arr[0]-arr[1],b=arr[0]-arr[2];
    for (int x=0;x<s.size();x++){
        ans=max(ans,suffix[ii(a-(pre[0]-pre[1]),b-(pre[0]-pre[2]))]-x);
        if (s[x]=='J') pre[0]++;
        else if (s[x]=='O') pre[1]++;
        else pre[2]++;
    }
    printf("%d\n",ans);
}

Compilation message (stderr)

joioji.cpp: In member function 'size_t custom_hash::operator()(const std::pair<int, int>&) const':
joioji.cpp:28:75: warning: suggest parentheses around arithmetic in operand of '|' [-Wparentheses]
         return splitmix64(((long long)i.first)|(((long long)i.second)<<32)+FIXED_RANDOM);
                                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
joioji.cpp: In function 'int main()':
joioji.cpp:50:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int x=0;x<s.size();x++){
                  ~^~~~~~~~~
joioji.cpp:59:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int x=0;x<s.size();x++){
                  ~^~~~~~~~~
joioji.cpp:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 80