Submission #648788

#	Time	Username	Problem	Language	Result	Execution time	Memory
648788		ymm	Regions (IOI09_regions)	C++17	1 / 100	5938 ms	131072 KiB

regions

#include <bits/stdc++.h>
#define Loop(x,l,r) for (ll x = (l); x < (ll)(r); ++x)
#define LoopR(x,l,r) for (ll x = (r)-1; x >= (ll)(l); --x)
typedef long long ll;
typedef std::pair<int, int> pii;
typedef std::pair<ll , ll > pll;
using namespace std;

const int S = 128;
const int N = 400'032 + S;
const int R = 25'010;
int reg[N];
int len = 0;
int exp_reg[N];
int delta[N];
char compress[N/S][R];
vector<int> bl_regs[N/S];
int cnt[N/S][S+1];
int scnt[N/S][S+1];
short sum[N/S][S+1][S+1];
vector<int> A[N];
int n, r, q;

void dfs(int v)
{
	exp_reg[len] = reg[v];
	delta[len] = 1;
	++len;
	for (int u : A[v])
		dfs(u);
	exp_reg[len] = reg[v];
	delta[len] = -1;
	++len;
}

void calc_block(int bl)
{
	int l = bl*S, r = min(bl*S+S, len);
	int ans[S][S] = {}, pre[S] = {};
	Loop (i,l,r) {
		int reg = compress[bl][exp_reg[i]];
		Loop (j,0,S)
			ans[reg][j] += pre[j];
		pre[reg] += delta[i];
	}
	Loop (i,0,S) Loop (j,0,S)
		sum[bl][i][j] = ans[j][i];
}

void comp_block(int bl)
{
	int l = bl*S, r = min(bl*S+S, len);
	Loop (i,l,r)
		bl_regs[bl].push_back(exp_reg[i]);
	sort(bl_regs[bl].begin(), bl_regs[bl].end());
	bl_regs[bl].resize(  unique(bl_regs[bl].begin(), bl_regs[bl].end())
	                   - bl_regs[bl].begin());
	fill(compress[bl], compress[bl]+R, S);
	Loop (i,0,bl_regs[bl].size())
		compress[bl][bl_regs[bl][i]] = i;
}

void init()
{
	for (int l = 0; l < len; l += S)
	{
		int r = min(len, l + S);
		comp_block(l/S);
		calc_block(l/S);
		Loop (i,l,r) {
			 cnt[l/S][compress[l/S][exp_reg[i]]]++;
			scnt[l/S][compress[l/S][exp_reg[i]]] += delta[i];
		}
	}
}

int solve(int r1, int r2)
{
	int ans = 0, pre = 0;
	Loop (i,0,(len+S-1)/S) {
		int cr1 = compress[i][r1];
		int cr2 = compress[i][r2];
		ans += pre * cnt[i][cr2];
		ans += sum[i][cr1][cr2];
		pre += scnt[i][cr1];
	}
	return ans/2;
}

int main()
{
	cin.tie(0) -> sync_with_stdio(false);
	cin >> n >> r >> q;
	cin >> reg[0];
	Loop (i,1,n) {
		int p;
		cin >> p >> reg[i];
		A[p-1].push_back(i);
	}
	dfs(0);
	init();
	while (q--) {
		int r1, r2;
		cin >> r1 >> r2;
		cout << solve(r1, r2) << '\n';
		cout.flush();
	}
}

Compilation message (stderr)

regions.cpp: In function 'void init()':
regions.cpp:71:38: warning: array subscript has type 'char' [-Wchar-subscripts]
   71 |     cnt[l/S][compress[l/S][exp_reg[i]]]++;
      |              ~~~~~~~~~~~~~~~~~~~~~~~~^
regions.cpp:72:38: warning: array subscript has type 'char' [-Wchar-subscripts]
   72 |    scnt[l/S][compress[l/S][exp_reg[i]]] += delta[i];
      |              ~~~~~~~~~~~~~~~~~~~~~~~~^

• Subtask 1: 1 / 15
• Subtask 2: 0 / 85