Submission #213040

#	Time	Username	Problem	Language	Result	Execution time	Memory
213040		bash	Bitaro’s Party (JOI18_bitaro)	C++17	100 / 100	1888 ms	483832 KiB

bitaro

/**
Think about 1e5, what comes with limit 1e5
may be n*sqrt(n)
then think about how can we do
if sz > sqrt(n) then we can solve dummy o(n+m) in worst case o((n + m) * sqrt(n))
else we can store sqrt(n) furthest vertecies for all vertecies. (Because our query size < sqrt we will eventually find at least one ans)
*/
/**
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
*/
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <queue>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cassert>
 
#define F first
#define S second
#define endl '\n'
#define deb(x) cout<<#x<<' '<<x<<endl;
#define pb push_back
 using namespace __gnu_pbds;
using namespace std;

typedef tree<
int,
null_type,
less<int>,
rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;
/*
#ifdef IZI_KATKA
#define int __int64_t
#else
#define int __int64
#endif
*/
const long long MOD = 1e9 + 7;
const long long MAXN = 1e6 + 1;

typedef long long ll;

#define pii pair<int,int>
 
long long readInt() {
    bool minus1 = false;
    long long result = 0;
    char ch;
    ch = getchar();
    while (true) {
        if (ch == '-') break;
        if (ch >= '0' && ch <= '9') break;
        ch = getchar();
    }
    if (ch == '-') minus1 = true; else result = ch-'0';
    while (true) {
        ch = getchar();
        if (ch < '0' || ch > '9') break;
        result = result*10 + (ch - '0');
    }
    if (minus1)
        return -result;
    else
        return result;
}

int n;
int used[MAXN];
vector<int> g[MAXN];
vector<int> g_rev[MAXN];
int dp[MAXN];


int slow(int start) {
	fill(dp, dp + n + 1, -MOD);
	dp[start] = 0;
	int ans = -1;
	for (int i = start; i >= 1; i--) {
		for (int j : g[i]) {
			dp[i] = max(dp[i], dp[j] + 1);	
		}
		if (!used[i]) {
			ans = max(ans, dp[i]);
		}
	}	
	return ans;
}

vector<pii> kth[MAXN];
int sq;

void init() {
	for (int i = 1; i <= n; i++) {
		kth[i].pb({0, i});
		for (int j : g_rev[i]) {
			vector<pii> nxt = kth[j];
			vector<pii> prv = kth[i];
			kth[i].clear();
			int ptr = 0;
			for (auto k : nxt) {
				k.first++;
				while(ptr < prv.size() && prv[ptr].first >= k.first) {
					if (used[prv[ptr].second]) {
						ptr++;
						continue;
					}
					used[prv[ptr].second] = 1;
					kth[i].pb(prv[ptr]);
					ptr++;
				}
				if (used[k.second]) continue;
				used[k.second] = 1;
				kth[i].pb(k);
			}
			while(ptr < prv.size()){
				if(used[prv[ptr].second]){
					ptr++;
					continue;
				}
				used[prv[ptr].second] = 1;
				kth[i].push_back(prv[ptr]);
				ptr++;
			}
			for(auto &z : nxt) used[z.second] = 0;
			for(auto &z : prv) used[z.second] = 0;
			while(kth[i].size() > sq) kth[i].pop_back();
		}		
	}
}

int main() {
	#ifdef IZI_KATKA
	assert(freopen("input", "r", stdin));
    assert(freopen("output", "w", stdout));
    #endif
    n = readInt(); int m = readInt(), q = readInt();
    sq = sqrt(n);
    for (int i = 1; i <= m; i++) {
		int from = readInt(), to = readInt();
		g[from].pb(to);
		g_rev[to].pb(from);
    }
    init();
	while(q--) {
		int start = readInt();
		int sz = readInt();
		vector<int> tmp(sz);
		for (int &i : tmp) {
			i = readInt();			
			used[i] = 1;
		}
		if (sz >= sq) {	
			/// dummy sol
			cout << slow(start) << endl;
		} else {
			/// take sqrt(n) furthest vertecies
	    	int ans = -1;
	    	for (auto i : kth[start]) {
	    		if (!used[i.second]) {
	    			ans = i.first;
	    			break;
	    		}
	    	}
	    	cout << ans << endl;
		}
		for (int i : tmp) {
			used[i] = 0;
		}
	}    
    return 0;
}

Compilation message (stderr)

bitaro.cpp: In function 'void init()':
bitaro.cpp:121:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(ptr < prv.size() && prv[ptr].first >= k.first) {
           ~~~~^~~~~~~~~~~~
bitaro.cpp:134:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while(ptr < prv.size()){
          ~~~~^~~~~~~~~~~~
bitaro.cpp:145:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while(kth[i].size() > sq) kth[i].pop_back();
          ~~~~~~~~~~~~~~^~~~

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 86 / 86