交互题(apio2016Gap)
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//Serene #include<algorithm> #include<iostream> #include<cstring> #include<cstdlib> #include<cstdio> #include<cmath> #include "gap.h" using namespace std; #define ll long long #define db double #define For(i,a,b) for(int i=(a);i<=(b);++i) #define Rep(i,a,b) for(int i=(a);i>=(b);--i) ll findGap(int T,int N) { ll n=(N+1)>>1,l=0,r=1e18,ld,rd,rs=0,fl=0,len; if(T==1) { MinMax(l,r,&ld,&rd); l=ld; r=rd; For(i,1,n-1) { MinMax(l+1,r-1,&ld,&rd); rs=max(rs,ld-l); rs=max(rs,r-rd); l=ld; r=rd; if((r-1)-(l+1)<=rs) {fl=1; break;} } if(!fl) rs=max(rs,rd-ld); return rs; } else { MinMax(l,r,&ld,&rd); l=ld; r=rd; len=(r-l+N-2)/(N-1); ll lst=l; for(ll now=l;now<r-1;now+=len) { MinMax(now+1,min(now+len,r-1),&ld,&rd); if(~ld) rs=max(rs,ld-lst),lst=rd; } rs=max(rs,r-lst); return rs; } }
编译:
g++ -g gap.cpp grader.cpp -o gap
grader.cpp
#include <stdio.h> #include <stdlib.h> #include "gap.h" static void my_assert(int k){ if (!k) exit(1); } static int subtask_num, N; static long long A[100001]; static long long call_count; long long findGap(int, int); void MinMax(long long s, long long t, long long *mn, long long *mx) { int lo = 1, hi = N, left = N+1, right = 0; my_assert(s <= t && mn != NULL && mx != NULL); while (lo <= hi){ int mid = (lo+hi)>>1; if (A[mid] >= s) hi = mid - 1, left = mid; else lo = mid + 1; } lo = 1, hi = N; while (lo <= hi){ int mid = (lo+hi)>>1; if (A[mid] <= t) lo = mid + 1, right = mid; else hi = mid - 1; } if (left > right) *mn = *mx = -1; else{ *mn = A[left]; *mx = A[right]; } if (subtask_num == 1) call_count++; else if (subtask_num == 2) call_count += right-left+2; } int main() { // freopen("gap.in","r",stdin); // freopen("gap.out","w",stdout); FILE *in = stdin, *out = stdout; my_assert(2 == fscanf(in, "%d%d", &subtask_num, &N)); my_assert(1 <= subtask_num && subtask_num <= 2); my_assert(2 <= N && N <= 100000); for (int i=1;i<=N;i++) my_assert(1 == fscanf(in, "%lld", A+i)); for (int i=1;i<N;i++) my_assert(A[i] < A[i+1]); fprintf(out, "%lld\n", findGap(subtask_num, N)); fprintf(out, "%lld\n", call_count); }
gap.h
void MinMax(long long, long long, long long*, long long*);
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