AC 730

.gitignore

@@ -1,3 +1,4 @@
+.DS_Store
 .idea
 .vscode
 

leetcode/hard/730-slow.cc

@@ -0,0 +1,99 @@
+#include <cstring>
+#include <iostream>
+#include <string>
+
+using std::string;
+using std::cout; using std::endl;
+
+
+// for 'a' ~ 'd'
+static const int X_MAX = 'd' - 'a';
+static const int N_MAX = 1000;
+static int dp[3][N_MAX][N_MAX][X_MAX + 1];
+
+class Solution {
+private:
+    static const int MOD = 1000000007;
+
+public:
+    int countPalindromicSubsequences(string S) {
+        int n = S.size(), ans = 0, memset_size = sizeof(dp[0]);
+        memset(dp, 0, sizeof(dp));
+        for (int len = 1; len <= n; len++) {
+            for (int sep = len - 1; sep < n; sep ++) {
+                for (int i = 0; i + sep < n; i++) {
+                    int j = i + sep;
+                    int a = S[i] - 'a', b = S[j] - 'a';
+                    for (int x = 0; x <= X_MAX; x++)
+                        if (x != a && x != b && 1 < sep)
+                            dp[0][i][j][x] = dp[0][i + 1][j - 1][x];
+                    if (a == b) {
+                        if (len <= 2)
+                            dp[0][i][j][a] = 1;
+                        else
+                            for (int x = 0; x <= X_MAX; x++)
+                                dp[0][i][j][a] = (dp[0][i][j][a] + dp[2][i + 1][j - 1][x]) % MOD;
+                    } else if (0 < sep) {
+                        dp[0][i][j][a] = dp[0][i][j - 1][a];
+                        dp[0][i][j][b] = dp[0][i + 1][j][b];
+                    }
+                }
+            }
+            for (int x = 0; x <= X_MAX; x++)
+                ans = (ans + dp[0][0][n - 1][x]) % MOD;
+            // Use scrolling array to save memory
+            memcpy(dp[2], dp[1], memset_size);
+            memcpy(dp[1], dp[0], memset_size);
+            memset(dp[0], 0, memset_size);
+        }
+        return ans;
+    }
+};
+
+
+// Input: 
+// S = 'abcdabcdabcdabcdabcdabcdabcdabcddcbadcbadcbadcbadcbadcbadcbadcba'
+// Output: 104860361
+
+// bccb
+// len 0:
+// len 1: b c
+// len 2: bb cc
+// len 3: bcb
+// len 4: bccb
+
+// dp[1][0][0]['b'] = 1, dp[1][1][1]['c'] = 1, dp[1][2][2]['c'] = 1, dp[1][3][3]['b'] = 1
+
+// dp[len][i][j][x] means different palindroms count which start / end with 'x' between s[i] and s[j], length is len
+// loop len, sep, i
+// j = i + sep
+// for x != s[i] and x != s[j]:
+//                   dp[len][i][j][x] = dp[len][i + 1][j - 1][x]
+// s[i] == s[j] == a:
+//                   dp[len][i][j][a] = sum(dp[len - 2][i + 1][j - 1][every x])
+// s[i] == a, s[j] == b, a != b:
+//                   dp[len][i][j][a] = dp[len][i][j - 1][a],
+//                   dp[len][i][j][b] = dp[len][i + 1][j][b]
+
+
+int main() {
+    Solution* sol = new Solution;
+    string input;
+
+    input = "addd";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 4 << endl;
+
+    input = "bccb";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 6 << endl;
+
+    input = "abcdabcdabcdabcdabcdabcdabcdabcddcbadcbadcbadcbadcbadcbadcbadcba";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 104860361 << endl;
+
+    input = "baaddaaabaddccbbbdcbcccbdbdabdabdbadabddbbcbbcabbccdaccdbcbbcdcdbaadbcadacabcaaaadbcaddbbacddcdabaadcacacdcabaadacadcccdcbbcdabdcdacaacdcdbdacbdbcdcbaddaccabaaaabcadacdaddbcccbcdbadbdddaaabbdbdbcbcdab";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 431300010 << endl;
+
+    input = "bdccbdbdcaacaadbdacaadabbdaababacbdbadaccccbbbccbdbddcacdbbcdaaababddadbbcabaddbbaabcdacdcddcbacdcadddbaadcbbccdcbdcaaabcbddacaccadacdcadacadccabdbadcdabaaccbcabbacdcbbbabddbcccbcbcddacaccabbabccdbbabacadbbdbcccbddaaadcdaddcccddaacbddabddabadbcbaadcaddbdccabaddcccdccbacaccccbcdccacbabddcbcbbbdbbddaabbcaddbddddaacbbccbcdbadacccbadbccdddadcbacbbdcabcbdbbaabcdcbdacabacdccdaabcbbddbdddcacdbdccbbabbaccdcbabcdacdabdddaddacdbddabcbbbdcccacbdadddbbdbcabccadbcbadddcbcddaababcabbbcbbabadaddabcbdacaadcababcbacadcdabcdbddadaadddddbaaacddaacadcdbaaacbacaabdabccbacabbabddacddcdacdcddbacbddbdcadcddabdadcdbcbbcadbcdabbbbdcdadadbbcadbcbbcccccabdaabcdacbdbcadabcdbaaaaacdaaabcdcaabddcacdcacabbaadbdbcbaaabadbdadadaccddacababbdcbaaaccaabbdaddadcabaabbdaadadcabcabbdbbdccbabbbabbcbcbdcacccbdbabdbaadccdaddaddaadadccabdcbbbccacbbaaabccaccdcabbbddbdbbacdaabbdcdacbdddbacbadccabbbdbbbdbdbcadcacddddcdbdcabccdccabaadbcbacaaababdddcbcdaaabaaabddbcabcbbcdddccdcbccbbccadccaaccccbdadcaacdcbcabacacadaabacddaadcccbcabdad";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 739921586 << endl;
+
+    return 0;
+}

leetcode/hard/730.cc

@@ -0,0 +1,92 @@
+#include <iostream>
+#include <string>
+#include <vector>
+
+using std::string;
+using std::vector;
+using std::cout; using std::endl;
+
+class Solution {
+public:
+    int countPalindromicSubsequences(string S) {
+        int n = S.length();
+        vector<vector<long>> dp(n, vector<long>(n, 0));
+        for (int i = 0; i < n; i++)
+            dp[i][i] = 1;
+        for (int len = 1; len < n; len++) {
+            for (int i = 0; i + len < n; i++) {
+                int j = i + len;
+                if (S[i] == S[j]) {
+                    dp[i][j] = 2 * dp[i + 1][j - 1];
+                    int l = i + 1, r = j - 1;
+                    for (; l <= r && S[l] != S[i]; l++);
+                    for (; l <= r && S[r] != S[j]; r--);
+                    if (l == r)
+                        dp[i][j] += 1;
+                    else if (l > r)
+                        dp[i][j] += 2;
+                    else
+                        dp[i][j] -= dp[l + 1][r - 1];
+                } else {
+                    dp[i][j] = dp[i][j - 1] + dp[i + 1][j] - dp[i + 1][j - 1];
+                }
+                dp[i][j] = dp[i][j] % MOD;
+            }
+        }
+        return dp[0][n - 1];
+    }
+
+private:
+    static constexpr long MOD = 1000000007;
+};
+
+
+// Input: 
+// S = 'abcdabcdabcdabcdabcdabcdabcdabcddcbadcbadcbadcbadcbadcbadcbadcba'
+// Output: 104860361
+
+// bccb
+// len 0:
+// len 1: b c
+// len 2: bb cc
+// len 3: bcb
+// len 4: bccb
+
+// dp[i][j] means different palindroms count between i and j
+// loop len, i, j
+// init:
+//      dp[i][i] = 1
+// s[i] == s[j]:
+// CASE1: b ccbcc b   ->   +"bb"
+//          2 * count(ccbcc) + 1
+// CASE2: b c b       ->   +"b" +"bb"
+//          2 * count(c) + 2
+// CASE3: b ca b      ->   +"b" +"bb"
+//          2 * count(ca) + 2
+// CASE4: b bcab b    ->   -"bcb" -"bab"
+//          2 * count(bcab) - count(ca)
+// s[i] != s[j]:
+//      dp[i][j] = dp[i][j - 1] + dp[i + 1][j] - dp[i + 1][j - 1]
+
+
+int main() {
+    Solution* sol = new Solution;
+    string input;
+
+    input = "addd";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 4 << endl;
+
+    input = "bccb";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 6 << endl;
+
+    input = "abcdabcdabcdabcdabcdabcdabcdabcddcbadcbadcbadcbadcbadcbadcbadcba";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 104860361 << endl;
+
+    input = "baaddaaabaddccbbbdcbcccbdbdabdabdbadabddbbcbbcabbccdaccdbcbbcdcdbaadbcadacabcaaaadbcaddbbacddcdabaadcacacdcabaadacadcccdcbbcdabdcdacaacdcdbdacbdbcdcbaddaccabaaaabcadacdaddbcccbcdbadbdddaaabbdbdbcbcdab";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 431300010 << endl;
+
+    input = "bdccbdbdcaacaadbdacaadabbdaababacbdbadaccccbbbccbdbddcacdbbcdaaababddadbbcabaddbbaabcdacdcddcbacdcadddbaadcbbccdcbdcaaabcbddacaccadacdcadacadccabdbadcdabaaccbcabbacdcbbbabddbcccbcbcddacaccabbabccdbbabacadbbdbcccbddaaadcdaddcccddaacbddabddabadbcbaadcaddbdccabaddcccdccbacaccccbcdccacbabddcbcbbbdbbddaabbcaddbddddaacbbccbcdbadacccbadbccdddadcbacbbdcabcbdbbaabcdcbdacabacdccdaabcbbddbdddcacdbdccbbabbaccdcbabcdacdabdddaddacdbddabcbbbdcccacbdadddbbdbcabccadbcbadddcbcddaababcabbbcbbabadaddabcbdacaadcababcbacadcdabcdbddadaadddddbaaacddaacadcdbaaacbacaabdabccbacabbabddacddcdacdcddbacbddbdcadcddabdadcdbcbbcadbcdabbbbdcdadadbbcadbcbbcccccabdaabcdacbdbcadabcdbaaaaacdaaabcdcaabddcacdcacabbaadbdbcbaaabadbdadadaccddacababbdcbaaaccaabbdaddadcabaabbdaadadcabcabbdbbdccbabbbabbcbcbdcacccbdbabdbaadccdaddaddaadadccabdcbbbccacbbaaabccaccdcabbbddbdbbacdaabbdcdacbdddbacbadccabbbdbbbdbdbcadcacddddcdbdcabccdccabaadbcbacaaababdddcbcdaaabaaabddbcabcbbcdddccdcbccbbccadccaaccccbdadcaacdcbcabacacadaabacddaadcccbcabdad";
+    cout << "actual: " << sol->countPalindromicSubsequences(input) << ", expected: " << 739921586 << endl;
+
+    return 0;
+}

leetcode/hard/732.cc

@@ -0,0 +1,10 @@
+class MyCalendarThree {
+public:
+    MyCalendarThree() {
+        
+    }
+
+    int book(int start, int end) {
+        
+    }
+};