-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathLongestCommonSubSeqence.cpp
More file actions
108 lines (92 loc) · 3.31 KB
/
LongestCommonSubSeqence.cpp
File metadata and controls
108 lines (92 loc) · 3.31 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
/*
Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0.
A subsequence of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of the remaining characters.
For example, "ace" is a subsequence of "abcde".
A common subsequence of two strings is a subsequence that is common to both strings.
Example 1:
Input: text1 = "abcde", text2 = "ace"
Output: 3
Explanation: The longest common subsequence is "ace" and its length is 3.
Example 2:
Input: text1 = "abc", text2 = "abc"
Output: 3
Explanation: The longest common subsequence is "abc" and its length is 3.
Example 3:
Input: text1 = "abc", text2 = "def"
Output: 0
Explanation: There is no such common subsequence, so the result is 0.
*/
#include<bits/stdc++.h>
using namespace std;
class Solution {
public:
int helper(string s1,string s2,int n1,int n2,int memo[][1001])//Reason For TLE-We need
{ //to pass strings in parameters as a reference - like &s1,&s2
if(n1==0 || n2==0)
return memo[n1][n2]=0;
if(memo[n1][n2]!=-1)
return memo[n1][n2];
if(s1[n1-1]==s2[n2-1])
return memo[n1][n2]=1+helper(s1,s2,n1-1,n2-1,memo);
return memo[n1][n2]=max(helper(s1,s2,n1-1,n2,memo),helper(s1,s2,n1,n2-1,memo));
}
int longestCommonSubsequence(string text1, string text2) {
int n1=text1.length();
int n2=text2.length();
int memo[1001][1001];
for(int i=0;i<1001;i++)
for(int j=0;j<1001;j++)
memo[i][j]=-1;
int res=helper(text1,text2,n1,n2,memo);
return res;
}
};
//-----------------ACCEPTED MEMOIZATION SOLUTION-----------------//
class Solution {
public:
int longestCommonSubsequence(string &s1,string &s2,int n1,int n2,int memo[1001][1001])
{
if(n1==0 || n2==0)
return 0;
if(memo[n1][n2]!=-1)
return memo[n1][n2];
if(s1[n1-1]==s2[n2-1])
return memo[n1][n2]=1+longestCommonSubsequence(s1,s2,n1-1,n2-1,memo);
else
return memo[n1][n2]=max(longestCommonSubsequence(s1,s2,n1-1,n2,memo),longestCommonSubsequence(s1,s2,n1,n2-1,memo));
}
int longestCommonSubsequence(string text1, string text2) {
int n1=text1.size();
int n2=text2.size();
int memo[1001][1001];
for(int i=0;i<1001;i++)
for(int j=0;j<1001;j++)
memo[i][j]=-1;
return longestCommonSubsequence(text1,text2,n1,n2,memo);
}
};
//-----TABULATION SOLUTION-----//
//EFFICIENT SOLUTION - Bottom Up Approach
class Solution {
public:
int longestCommonSubsequence(string text1, string text2) {
int m=text1.size(),n=text2.size();
int dp[m+1][n+1];
for(int i=0;i<m+1;i++){
dp[i][0]=0;
}
for(int i=0;i<n+1;i++){
dp[0][i]=0;
}
for(int i=1;i<m+1;i++){
for(int j=1;j<n+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-1][j],dp[i][j-1]);
}
}
}
return dp[m][n];
}
};