dp_up::date

Author: cosmicray001

DP/LCS_loop.cpp

@@ -0,0 +1,15 @@
+    int longestCommonSubsequence(string text1, string text2) {
+        int dp[text1.size() + 1][text2.size() + 1];
+        memset(dp, 0, sizeof(dp));
+        for(int i = 1; i < text1.size() + 1; i++){
+            for(int j = 1; j < text2.size() + 1; j++){
+                if(text1[i - 1] == text2[j - 1]){
+                    dp[i][j] = 1 + dp[i - 1][j - 1];
+                }
+                else{
+                    dp[i][j] = max(dp[i][j - 1], dp[i - 1][j]);
+                }
+            }
+        }
+        return dp[text1.size()][text2.size()];
+    }

DP/LCS_memory_efficient_1loop.cpp

@@ -0,0 +1,14 @@
+int longestCommonSubsequence(string text1, string text2) {
+        int le = text2.size() + 1, p;
+        vector<int> st(le, 0);
+        for(int i = 1; i < text1.size() + 1; i++){
+            p = 0;
+            for(int j = 1; j < text2.size() + 1; j++){
+                int bu = st[j];
+                if(text1[i - 1] == text2[j - 1]) st[j] = p + 1;
+                else st[j] = max(st[j], st[j - 1]);
+                p = bu;
+            }
+        }
+        return st[text2.size()];
+    }

DP/LCS_memory_efficient_2loop.cpp

@@ -0,0 +1,13 @@
+int longestCommonSubsequence(string text1, string text2) {
+        int le = text2.size() + 2;
+        int ans = 0;
+        vector<int> prev(le, 0), cur(le, 0);
+        for(int i = 1; i < text1.size() + 1; i++){
+            for(int j = 1; j < text2.size() + 1; j++){
+                if(text1[i - 1] == text2[j - 1]) cur[j] = 1 + prev[j - 1];
+                else cur[j] = max(cur[j - 1], prev[j]);
+            }
+            for(int j = 0; j < text2.size() + 1; j++) prev[j] = cur[j];
+        }
+        return cur[text2.size()];
+    }

DP/LCS_recursion.cpp

@@ -0,0 +1,8 @@
+int fnc(int i, int j, string s, string t){
+    if(i == s.size() || j == t.size()) return 0;
+    if(dp[i][j] != 0) return dp[i][j];
+    int ans = 0;
+    if(s[i] == t[j]) ans = 1 + fnc(i + 1, j + 1, s, t);
+    else ans = max(fnc(i + 1, j, s, t, ), fnc(i, j + 1, s, t));
+    return dp[i][j] = ans;
+}

code_book.cpp

@@ -929,7 +929,8 @@ int main(){
   printf("%d\n", ans[ans.size() - 1]);
   return 0;
 }
------------------------------------------------------------- recursionallPossibleSubSet
+------------------------------------------------------------ 
+recursionallPossibleSubSet
 ------------------------------------------------------------
 #include <bits/stdc++.h>
 #define le 10002
@@ -947,6 +948,43 @@ int main(){
   }
   return 0;
 }
+------------------------------------------------------------ 
+N_queens_problem
+------------------------------------------------------------
+    vector<vector<string>> ans;
+    bool ck(vector<string>& s, int r, int c){
+        for(int i = 0; i < s.size(); i++) if(s[i][c] == 'Q') return false;
+        for(int i = r, j = c; i >= 0 && j >= 0; i--, j--) if(s[i][j] == 'Q') return false;
+        for(int i = r, j = c; i >= 0 && j < s.size(); i--, j++) if(s[i][j] == 'Q') return false;
+        return true;
+    }
+    void fnc(vector<string>& s, int r){
+        if(r == s.size()){
+            ans.push_back(s);
+            return;
+        }
+        for(int i = 0; i < s.size(); i++){
+            if(ck(s, r, i)){
+                s[r][i] = 'Q';
+                fnc(s, r + 1);
+                s[r][i] = '.';
+            }
+        }
+    }
+    vector<vector<string>> solveNQueens(int n) {
+        vector<string> N;
+        for(int i = 0; i < n; i++){
+            string s = "";
+            for(int j = 0; j < n; j++) s += '.';
+            N.push_back(s);
+        }
+        fnc(N, 0);
+        return ans;
+    }
+------------------------------------------------------------
+LCS && path
+------------------------------------------------------------
+
 ------------------------------------------------------------
 LCS && path
 ------------------------------------------------------------

recursion_backtrack/Nqueens_problem.cpp

@@ -0,0 +1,30 @@
+    vector<vector<string>> ans;
+    bool ck(vector<string>& s, int r, int c){
+        for(int i = 0; i < s.size(); i++) if(s[i][c] == 'Q') return false;
+        for(int i = r, j = c; i >= 0 && j >= 0; i--, j--) if(s[i][j] == 'Q') return false;
+        for(int i = r, j = c; i >= 0 && j < s.size(); i--, j++) if(s[i][j] == 'Q') return false;
+        return true;
+    }
+    void fnc(vector<string>& s, int r){
+        if(r == s.size()){
+            ans.push_back(s);
+            return;
+        }
+        for(int i = 0; i < s.size(); i++){
+            if(ck(s, r, i)){
+                s[r][i] = 'Q';
+                fnc(s, r + 1);
+                s[r][i] = '.';
+            }
+        }
+    }
+    vector<vector<string>> solveNQueens(int n) {
+        vector<string> N;
+        for(int i = 0; i < n; i++){
+            string s = "";
+            for(int j = 0; j < n; j++) s += '.';
+            N.push_back(s);
+        }
+        fnc(N, 0);
+        return ans;
+    }