Submission #40729

#TimeUsernameProblemLanguageResultExecution timeMemory
40729ssnsarang2023Boat (APIO16_boat)C++14
0 / 100
8 ms1400 KiB
#include <bits/stdc++.h> using namespace std; typedef long long ll; typedef unsigned long long ull; typedef pair<int, int> ii; #define SZ(x) ((int)x.size()) const int mod = (int)1e9+7; const int N = 505; int n, f[N], g[N], ftmp[N], gtmp[N], a[N], b[N], inv[N]; int choose[N][N], nCk[N], nCk2[N], choose1[N][N], choose2[N][N]; vector<int> c, gg[2*N]; int mul(int x, int y) { x %= mod, y %= mod; if (x < 0) x += mod; if (y < 0) y += mod; return (int)((ll)x * (ll)y % (ll)mod); } void add(int &x, int y) { x += y, x %= mod; if (x < 0) x += mod; } int fast_pw(int x, int y) { if (y == 1) return x % mod; if (y == 0) return 1; int t = fast_pw(x, y >> 1); t = mul(t, t); if (y & 1) t = mul(t, x); return t; } int main() { scanf("%d", &n); for (int i = 1; i <= n; ++i) { scanf("%d%d", &a[i], &b[i]); c.push_back(a[i]); c.push_back(b[i]); } sort(c.begin(), c.end()); c.resize(distance(c.begin(), unique(c.begin(), c.end()))); for (int i = 0; i <= n; ++i) choose[i][i] = choose[i][0] = 1; inv[0] = f[0] = g[0] = 1; for (int i = 1; i <= n; ++i) { int lo = lower_bound(c.begin(), c.end(), a[i]) - c.begin(); int hi = lower_bound(c.begin(), c.end(), b[i]) - c.begin(); for (int j = lo; j <= hi; ++j) gg[j].push_back(i); for (int j = 1; j < i; ++j) choose[i][j] = (choose[i - 1][j - 1] + choose[i - 1][j]) % mod; inv[i] = mul(inv[i - 1], fast_pw(i, mod - 2)); add(g[i], g[i - 1]); } for (int i = 0; i < SZ(c) - 1; ++i) { vector<int> tmp; for (int j = 0; j < SZ(gg[i]); ++j) if (b[gg[i][j]] == c[i]) ftmp[gg[i][j]] = gtmp[gg[i][j]] = g[gg[i][j] - 1]; else tmp.push_back(gg[i][j]); for (int j = 1; j <= n; ++j) add(gtmp[j], gtmp[j - 1]); int total = c[i + 1] - c[i], tmp_mul1 = 1, tmp_mul2 = 1; for (int j = 1; j <= min(total, SZ(tmp)); ++j) { tmp_mul1 = mul(tmp_mul1, total - j + 1); tmp_mul2 = mul(tmp_mul2, total - j); nCk[j] = mul(tmp_mul1, inv[j]); nCk2[j] = mul(tmp_mul2, inv[j]); } for (int j = 0; j <= min(total, SZ(tmp)) - 2; ++j) { for (int k = 0; k <= j; ++k) { choose1[j][k] = mul(choose[j][k], nCk[k + 2]); if (j <= min(total - 1, SZ(tmp) - 2)) choose2[j][k] = mul(choose[j][k], nCk2[k + 2]); add(choose1[j][k], choose1[j][k - 1]); add(choose2[j][k], choose2[j][k - 1]); } } for (int j = SZ(tmp) - 1; j >= 0; --j) { int id = tmp[j]; ftmp[id] = (ftmp[id] + mul(nCk[1], g[id - 1])) % mod; if (total > 1 && j > 0) { for (int k = j - 1; k >= 0; --k) { int mid = j - k - 1, id2 = tmp[k]; add(ftmp[id], mul(g[id2 - 1], choose1[mid][min(mid, total - 2)])); if (total > 2) add(ftmp[id], mul(gtmp[id2 - 1], choose2[mid][min(mid, total - 3)])); } } } for (int i = 1; i <= n; ++i) { add(f[i], ftmp[i]); g[i] = (g[i - 1] + f[i]) % mod; } } for (int i = 0; i < SZ(gg[SZ(c) - 1]); ++i) { int id = gg[SZ(c) - 1][i]; add(f[id], g[id - 1]); } int res = 0; for (int i = 1; i <= n; ++i) add(res, f[i]); printf("%lld", res); return 0; }

Compilation message (stderr)

boat.cpp: In function 'int main()':
boat.cpp:100:20: warning: format '%lld' expects argument of type 'long long int', but argument 2 has type 'int' [-Wformat=]
  printf("%lld", res);
                    ^
boat.cpp:39:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
boat.cpp:41:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a[i], &b[i]);
                              ^
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