Submission #1768823

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Source Code Expand

#include <cstdio>
#include <cstring>
#include <string>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <vector>
using namespace std;
typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> PII;
typedef vector<int> VI;
#define fi first
#define se second
#define MP make_pair

int read()
{
    int v = 0, f = 1;
    char c = getchar();
    while (c < 48 || 57 < c) {if (c == '-') f = -1; c = getchar();}
    while (48 <= c && c <= 57) v = (v << 3) + v + v + c - 48, c = getchar();
    return v * f;
}

const int N = 2e5 + 10;
const ll MOD = 1e9 + 7;
const int INF = 2e9;

ll f[N], g[N], mi[N];
int L[N], R[N], n, mx[N], mn[N];
PII a[N];
VI V[N];

ll query(int i, int j)
{
    if (i == 0)
        return g[j];
    else
        return (g[j] - g[i - 1] + MOD) % MOD;
}

int main()
{
    n = read();
    mi[0] = 1;
    for (int i = 1; i <= n; i++)
        mi[i] = mi[i - 1] * 2 % MOD;
    for (int i = 1; i <= n; i++)
    {
        int x = read(), v = read();
        a[i] = MP(v, x);
    }
    sort(a + 1, a + n + 1);
    for (int i = 1; i <= n; i++)
        mx[i] = max(mx[i - 1], a[i].se);
    mn[n + 1] = INF;
    for (int i = n; i >= 1; i--)
        mn[i] = min(mn[i + 1], a[i].se);
    for (int i = 1; i <= n; i++)
    {
        int l = 1, r = i;
        while (l < r)
        {
            int mid = l + r >> 1;
            if (mx[mid] >= a[i].se)
                r = mid;
            else
                l = mid + 1;
        }
        L[i] = l;
    }
    for (int i = 1; i <= n; i++)
    {
        int l = i, r = n;
        while (l < r)
        {
            int mid = l + r + 1 >> 1;
            if (mn[mid] <= a[i].se)
                l = mid;
            else
                r = mid - 1;
        }
        R[i] = l;
    }
    for (int i = 1; i <= n; i++)
        V[R[i]].push_back(L[i]);
    f[0] = 1;
    g[0] = 1;
    for (int i = 1; i <= n; i++)
    {
        sort(V[i].begin(), V[i].end());
        for (int j = 0; j < V[i].size(); j++)
            (f[i] += query(V[i][j] - 1, i - 1) * mi[V[i].size() - j - 1] % MOD) %= MOD;
        g[i] = (g[i - 1] + f[i]) % MOD;
    }
    printf("%lld\n", f[n]);
}

Submission Info

Judge Result