Add more problems

CSES Problem Set/Graph Paths I.cpp

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+/* Problem URL: https://cses.fi/problemset/task/1723 */
+ 
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+ 
+using namespace std;
+using namespace __gnu_pbds;
+ 
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+ 
+#define V vector
+ 
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+ 
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+ 
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+ 
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+ 
+using ll = long long;
+ 
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+ 
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+ 
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+ 
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+ 
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+ 
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+ 
+ 
+void pre()
+{
+ 
+}
+ 
+#define TEST 0
+ 
+void solve()
+{
+    int n, m, k;
+    cin >> n >> m >> k;
+ 
+    vvl adj(n, vl(n));
+ 
+    while (m--) {
+        int a, b;
+        cin >> a >> b;
+        adj[a - 1][b - 1]++;
+    }
+ 
+    ll mod = 1e9 + 7;
+ 
+    auto mul = [&](vvl &a, vvl &b) {
+        vvl c(a.size(), vl(b[0].size()));
+ 
+        rep(i, c.size()) {
+            rep(j, c[0].size()) {
+                rep(k, b.size()) {
+                    c[i][j] += a[i][k] * b[k][j];
+                    c[i][j] %= mod;
+                }
+            }
+        }
+ 
+        return c;
+    };
+ 
+    auto fpow = [&]() {
+        vvl ans(n, vl(n));
+        rep(i, n) {
+            ans[i][i] = 1;
+        }
+ 
+        rep(i, 30) {
+            if ((k >> i) & 1) {
+                ans = mul(ans, adj);
+            }
+            adj = mul(adj, adj);
+        }
+ 
+        return ans;
+    };
+ 
+    auto ans = fpow();
+ 
+    cout << ans[0][n - 1] << '\n';
+}
+ 
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+ 
+    pre();
+ 
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}