Submission #1030681

#	Time	Username	Problem	Language	Result	Execution time	Memory
1030681		sleepntsheep	Colors (BOI20_colors)	C11	0 / 100	0 ms	344 KiB

Colors

#define CF_SUBWAY_SURFER
#include<time.h>
#include<stdio.h>
#include<math.h>
#include<stdlib.h>
int h(int i,int j){return i>j?i:j;}
int h_(int i,int j){return -h(-i,-j);}
int a_,past_ask[66],b_;
int asked(long long c){for(int j=0;j<b_;++j)if(past_ask[j]==c)return 1;return 0;}
int ask(long long c){for(int j=0;j<b_;++j)if(past_ask[j]==c)return -1;past_ask[b_++]=c;printf("? %lld\n",c);fflush(stdout);scanf("%d",&a_);return a_;}
#define report(x) do{printf("= %lld\n",(long long)(x));fflush(stdout);goto X;}while(0)
int main(){
    srand(8686868);
    int t;
#ifndef CF_SUBWAY_SURFER
    t=1;
#else
    scanf("%d",&t);
#endif
    while(t--){
        b_=0;
        long long n;
        scanf("%lld",&n);
        if(n==1)report(1);
        if(n<=64){
            ask(1);
            if(!ask(n))report(n);
            for(int r=n-1,l=2,d=n-1,i=1,cc=0;cc<n-2;++i,--d,++cc)if((i%2&&!ask(l++)) || (i%2==0&&!ask(r--)))report(d);
            report(1);
        }
        if(n<=125){
            int m = n / 2 + 1;
            ask(m);
            int mid = ask(1);
            if (!ask(n))report(n);
            if(mid){
                for(int r=m-1,l=2,d=m-1,i=1,cc=0;d>1;++i,--d,++cc)
                    if(i%2&&!ask(l++))report(d);
                    else if(i%2==0&&!ask(r--))report(d);
                report(1);
            }else{
                for(int r=n-1,l=2,d=n-1,i=1,cc=0;d>1;++i,--d,++cc){
                    if(i%2){
                        if(l==m)report(1);
                        if(!ask(l++))report(d);
                    }
                    else{
                        if(r==m)report(1);
                        else if(!ask(r--)) report(d);
                    }
                }
                report(1);
            }
        }
        if(n<=1000){
            int S=34,m=n/2+1;
            ask(m);
            if (ask(m+1))report(1);
            ask(m);
            int ll=m,rr=m;
            for(int ii=1;;ii^=1){
                if(ii){
                    ll=h(ll-S,1);
                    if(ask(ll)){
                        for(int r=rr-1,l=ll+1,d=rr-ll,i=0;d>1;++i,--d)
                            if(i%2){ if(!ask(l++))report(d); }
                            else{ if(!ask(r--))report(d); }
                        report(rr-ll);
                    }
                }else{
                    rr=h_(rr+S,n);
                    if(ask(rr)){
                        for(int r=rr-1,l=ll+1,d=rr-ll,i=1;d>1;++i,--d)
                            if(i%2){ if(!ask(l++))report(d); }
                            else{ if(!ask(r--))report(d); }
                        report(rr-ll);
                    }
                }
                if (ll==1&&rr==n)
                    report(n);
            }
            report(n);
        }
        else if(n<=1e9){
            ask(1);
            int lb=0,ub=n;
            while(ub-lb>1){
                int md=lb+(ub-lb)/2;
                int v=1,xx,yy;
                while(asked(v)||asked(v+md)||v+md>n)
                    v=rand()*1ll*rand()%n+1;
                ask(v);
                yy=ask(v+md);
                if(yy)ub=md;
                else lb=md;
            }
            report(ub);
        }
X:;
    }
}

Compilation message (stderr)

Colors.c: In function 'main':
Colors.c:89:25: warning: unused variable 'xx' [-Wunused-variable]
   89 |                 int v=1,xx,yy;
      |                         ^~
Colors.c: In function 'ask':
Colors.c:10:124: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 | int ask(long long c){for(int j=0;j<b_;++j)if(past_ask[j]==c)return -1;past_ask[b_++]=c;printf("? %lld\n",c);fflush(stdout);scanf("%d",&a_);return a_;}
      |                                                                                                                            ^~~~~~~~~~~~~~~
Colors.c: In function 'main':
Colors.c:18:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |     scanf("%d",&t);
      |     ^~~~~~~~~~~~~~
Colors.c:23:9: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |         scanf("%lld",&n);
      |         ^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 13
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 33