이 제출은 이전 버전의 oj.uz에서 채점하였습니다. 현재는 제출 당시와는 다른 서버에서 채점을 하기 때문에, 다시 제출하면 결과가 달라질 수도 있습니다.
#include <functional>
#include <iostream>
#include <cstring>
#include <vector>
using namespace std;
const int MAXN = 1e6 + 5;
int n;
int a[MAXN][2];
namespace MaxA
{
int memo[MAXN][2];
int rec(int ind, int lastChoice)
{
if(ind==n) return 0;
int ans = -MAXN;
int lastVal = ((ind==0)?-1:a[ind-1][lastChoice]);
for(int c = 0;c<2;c++)
{
if(lastVal<=a[ind][c])
ans = max(ans, (c==0) + rec(ind+1, c));
}
return ans;
}
vector <int> solve()
{
memset(memo, -1, sizeof(memo));
vector <int> ans = {};
int aCnt = rec(0, 0), lastVal = -1;
for(int i = 0;i<n;i++)
{
for(int c = 0;c<2;c++)
{
if(lastVal<=a[i][c] && (c==0) + rec(i+1, c)==aCnt)
{
ans.push_back(c);
aCnt -= (c==0);
lastVal = a[i][c];
break;
}
}
}
return ans;
}
}
pair <int, int> maxB[MAXN];
int main()
{
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;n *= 2;
for(int i = 0;i<n;i++) cin >> a[i][0];
for(int i = 0;i<n;i++) cin >> a[i][1];
for(int i = 0;i<n-1;i++)
{
if(min(a[i][0], a[i][1])>max(a[i+1][0], a[i+1][1]))
{
cout << "-1" << '\n';
return 0;
}
}
int aCnt = 0;
vector <int> s = MaxA::solve();
for(int i = 0;i<n;i++) aCnt += (s[i]==0);
if(aCnt<n/2)
{
cout << "-1" << '\n';
return 0;
}
for(int i = 0;i<n;i++)
{
maxB[i] = {0, 0};
if(i!=0) maxB[i] = max(maxB[i], make_pair(maxB[i-1].first, 0));
if(i==n-1 || a[i][1]<=a[i+1][s[i+1]])
{
for(int j = i;j>=0;j--)
{
if(s[j]==1) break;
if(j!=i && a[j][1]>a[j+1][1]) break;
if(j==0 || a[j-1][s[i-1]]<=a[j][1])
{
int val = ((j-2>=0)?maxB[j-2].first:0);
maxB[i] = max(maxB[i], make_pair(val+(i-j+1), (i-j+1)));
}
}
}
}
int ind = -1;
int toCompensate = aCnt - n/2;
for(int i = 0;i<n;i++)
{
//cout << maxB[i].first << " " << maxB[i].second << '\n';
if(maxB[i].first>=toCompensate)
{
//ind = i;
//break;
}
}
if(maxB[n-1].first>=toCompensate) ind = n - 1;
if(ind==-1)
{
cout << "-1" << '\n';
return 0;
}
while(toCompensate!=0)
{
if(ind<0)
{
cout << 1/0 << '\n';
return 0;
}
if(maxB[ind].first<=toCompensate)
{
toCompensate -= maxB[ind].second;
for(int i = ind-maxB[ind].second+1;i<=ind;i++)
s[i] = 1;
ind = ind - maxB[ind].second - 1;
}
else
{
//cout << "OK " << ind << '\n';
int l = ind - maxB[ind].second + 1;
int r = ind;
function <bool(int)> check = [&](int i)
{
if(s[i]==1) return false;
if(i==0 || a[i-1][s[i-1]]<=a[i][1])
{
if(i==n-1 || a[i][1]<=a[i+1][s[i+1]])
{
return true;
}
}
return false;
};
bool found = false;
for(int i = l;i<=r;i++)
{
if(l==0 || a[l-1][s[l-1]]<=a[l][1])
{
if(i==n-1 || a[i][1]<=a[i+1][s[i+1]])
{
if(i-l+1==toCompensate)
{
for(int j = l;j<=i;j++)
{
s[j] = 1;
}
found = true;
break;
}
}
}
if(r==n-1 || a[r][1]<=a[r+1][s[r+1]])
{
if(i==0 || a[i-1][s[i-1]]<=a[i][1])
{
if(r-i+1==toCompensate)
{
for(int j = i;j<=r;j++)
{
s[j] = 1;
}
found = true;
break;
}
}
}
}
if(found==false)
{
//cout << 1/0 << '\n';
//return 0;
}
break;
}
}
for(int x: s) cout << char('A'+x);
cout << '\n';
}
컴파일 시 표준 에러 (stderr) 메시지
building4.cpp: In function 'int main()':
building4.cpp:135:22: warning: division by zero [-Wdiv-by-zero]
135 | cout << 1/0 << '\n';
| ~^~
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