atcoder/abc071D

Author: xirc

atcoder/abc071/D/main.cpp

@@ -0,0 +1,54 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+using ll = long long;
+
+ll MOD = 1000000007;
+
+int N;
+vector<string> S(2);
+
+ll solve() {
+    vector<ll> DP(N, 0);
+    for (int x = 0; x < N; ++x) {
+        if (S[0][x] == S[1][x]) {
+            if (x == 0) {
+                // |
+                DP[x] = 3;
+            } else if (S[0][x-1] == S[1][x-1]) {
+                // ||
+                DP[x] = DP[x-1] * 2 % MOD;
+            } else {
+                // =|
+                DP[x] = DP[x-1];
+            }
+        } else if (x > 0 && S[0][x] == S[0][x-1]) {
+            // =
+            DP[x] = DP[x-1];
+        } else {
+            if (x == 0) {
+                // =
+                DP[x] = 6;
+            } else if (S[0][x-1] == S[1][x-1]) {
+                // |=
+                DP[x] = DP[x-1] * 2 % MOD;
+            } else {
+                // ==
+                DP[x] = DP[x-1] * 3 % MOD;
+            }
+        }
+    }
+    return DP[N-1];
+}
+
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(0); cout.tie(0);
+
+    cin >> N;
+    cin >> S[0] >> S[1];
+    cout << solve() << endl;
+
+    return 0;
+}