OpenSoure_Repos/TheAlgorithms-C-Plus-Plus
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improved the code

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This commit is contained in:
Christian Bender 2018-03-27 23:14:19 +02:00
parent cc9e8d0d17
commit d3185357bd
1 changed files with 69 additions and 57 deletions
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126
Dynamic Programming/Longest Common Subsequence.cpp
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@ -4,63 +4,75 @@ using namespace std;
void Print(int trace[20][20], int m, int n, string a)
{
if (m==0 || n==0)
{
return;
}
if (trace[m][n]==1)
{
Print(trace, m-1, n-1, a);
cout<<a[m-1];
}
else if(trace[m][n]==2)
{
Print(trace, m-1,n, a);
}
else if (trace[m][n]==3)
{
Print(trace, m,n-1, a);
}
if (m==0 || n==0)
{
return;
}
if (trace[m][n]==1)
{
Print(trace, m-1, n-1, a);
cout<<a[m-1];
}
else if(trace[m][n]==2)
{
Print(trace, m-1,n, a);
}
else if (trace[m][n]==3)
{
Print(trace, m,n-1, a);
}
}
int lcs(string a, string b){
int m = a.length(), n = b.length();
int res[m+1][n+1];
int trace[20][20];
for (int i = 0; i < m+1; ++i)
{
for (int j = 0; j < n+1; ++j)
{
if(i==0||j==0)
{
res[i][j] = 0;
trace[i][j]=0;
}
else if(a[i-1]==b[j-1])
{
res[i][j] = 1 + res[i-1][j-1];
trace[i][j]=1; // 1 means trace the matrix in upper left diagonal direction.
}
else
{
if (res[i-1][j]>res[i][j-1])
{
res[i][j]=res[i-1][j];
trace[i][j]=2; // 2 means trace the matrix in upwards direction.
}
else
{
res[i][j]=res[i][j-1];
trace[i][j]=3; // means trace the matrix in left direction.
}
}
}
}
Print(trace, m, n, a);
return res[m][n];
int lcs(string a, string b)
{
int m = a.length(), n = b.length();
int res[m+1][n+1];
int trace[20][20];
// fills up the arrays with zeros.
for (int i = 0; i < m+1; i++)
{
for (int j = 0; j < n+1; j++)
{
res[i][j] = 0;
trace[i][j] = 0;
}
}
for (int i = 0; i < m+1; ++i)
{
for (int j = 0; j < n+1; ++j)
{
if(i==0||j==0)
{
res[i][j] = 0;
trace[i][j]=0;
}
else if(a[i-1]==b[j-1])
{
res[i][j] = 1 + res[i-1][j-1];
trace[i][j]=1; // 1 means trace the matrix in upper left diagonal direction.
}
else
{
if (res[i-1][j]>res[i][j-1])
{
res[i][j]=res[i-1][j];
trace[i][j]=2; // 2 means trace the matrix in upwards direction.
}
else
{
res[i][j]=res[i][j-1];
trace[i][j]=3; // means trace the matrix in left direction.
}
}
}
}
Print(trace, m, n, a);
return res[m][n];
}
@ -68,8 +80,8 @@ int lcs(string a, string b){
int main()
{
string a,b;
cin>>a>>b;
cout<<lcs(a,b);
return 0;
string a,b;
cin>>a>>b;
cout<<lcs(a,b);
return 0;
}