Submission #436854

#	Time	Username	Problem	Language	Result	Execution time	Memory
436854		adamjinwei	Mecho (IOI09_mecho)	C++14	76 / 100	493 ms	12476 KiB

mecho

#include <bits/stdc++.h>
#define inf 100000000000000007
#define mod 1000000007
#define rnd() dist(rand_num)
//#pragma GCC optimize("Ofast","inline","-ffast-math")
//#pragma GCC target("avx,sse2,sse3,sse4,mmx")
#define int long long
using namespace std;
unsigned seed=std::chrono::system_clock::now().time_since_epoch().count();
mt19937 rand_num(seed);
uniform_int_distribution<int> dist(0,inf);
template <typename T> void read(T &x){
	x=0;char ch=getchar();int fh=1;
	while (ch<'0'||ch>'9'){if (ch=='-')fh=-1;ch=getchar();}
	while (ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
	x*=fh;
}
template <typename T> void write(T x) {
	if (x<0) x=-x,putchar('-');
	if (x>9) write(x/10);
	putchar(x%10+'0');
}
template <typename T> void writeln(T x) {
	write(x);
	puts("");
}
const int dx[]={-1,0,1,0},dy[]={0,-1,0,1};
int n,s;
char mp[805][1005];
int bee[805][805];
int bear[805][805];
bool check(int mid)
{
	memset(bear,0x3f,sizeof(bear));
	queue<pair<int,int>> q;
	for(int i=1;i<=n;++i)
		for(int j=1;j<=n;++j)
			if(mp[i][j]=='M')
			{
				if(mid>=bee[i][j]) return false;
				bear[i][j]=mid;
				q.push(make_pair(i,j));
			}
	while(!q.empty())
	{
		pair<int,int> p=q.front();
		q.pop();
		for(int d=0;d<4;++d)
		{
			int xx=p.first+dx[d],yy=p.second+dy[d];
			if(xx>=1&&xx<=n&&yy>=1&&yy<=n&&mp[xx][yy]!='T'&&mp[xx][yy]!='H'&&bear[p.first][p.second]+1<bee[xx][yy]&&bear[xx][yy]>bear[p.first][p.second]+1)
			{
				bear[xx][yy]=bear[p.first][p.second]+1;
				q.push(make_pair(xx,yy));
			}
		}
	}
	for(int i=1;i<=n;++i)
		for(int j=1;j<=n;++j)
			if(mp[i][j]=='D')
			{
				if(bear[i][j]<inf) return true;
				return false;
			}
}
signed main()
{
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	read(n);read(s);
	for(int i=1;i<=n;++i)
		scanf("%s",mp[i]+1);
	memset(bee,0x3f,sizeof(bee));
	queue<pair<int,int>> q;
	for(int i=1;i<=n;++i)
		for(int j=1;j<=n;++j)
			if(mp[i][j]=='H')
			{
				bee[i][j]=0;
				q.push(make_pair(i,j));
			}
	while(!q.empty())
	{
		pair<int,int> p=q.front();
		q.pop();
		for(int d=0;d<4;++d)
		{
			int xx=p.first+dx[d],yy=p.second+dy[d];
			if(xx>=1&&xx<=n&&yy>=1&&yy<=n&&(mp[xx][yy]=='G'||mp[xx][yy]=='M')&&bee[xx][yy]>bee[p.first][p.second]+s)
			{
				bee[xx][yy]=bee[p.first][p.second]+s;
				q.push(make_pair(xx,yy));
			}
		}
	}
	int l=0,r=5000000;
	while(l<r)
	{
		int mid=l+r+1>>1;
		if(check(mid)) l=mid;
		else r=mid-1;
	}
	if(check(l)) writeln(l/s);
	else puts("-1");
	return 0;
}

Compilation message (stderr)

mecho.cpp: In function 'int main()':
mecho.cpp:99:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   99 |   int mid=l+r+1>>1;
      |           ~~~^~
mecho.cpp: In function 'bool check(long long int)':
mecho.cpp:35:23: warning: control reaches end of non-void function [-Wreturn-type]
   35 |  queue<pair<int,int>> q;
      |                       ^
mecho.cpp: In function 'int main()':
mecho.cpp:72:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |   scanf("%s",mp[i]+1);
      |   ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 76 / 100