/
intersection point of 2 ll.cpp
216 lines (152 loc) Β· 3.13 KB
/
intersection point of 2 ll.cpp
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
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
/*
///////////////////////////////////////////
//Question/Info
find intersection point of two ll
///////////////////////////////////////////
*/
#include <bits/stdc++.h>
using namespace std;
#define int long long int
#define setbits(x) __builtin_popcount(x)
#define pb(x) push_back(x)
#define mp(x,y) make_pair(x,y)
#define ct(x) cout<<x<<endl;
#define ct2(x,y) cout<<x<<" "<<y<<endl;
#define forn(i,n) for(int i = 0; i < (int)(n); i++)
#define forx(i,x,n) for(int i = x; i < (int)(n); i++)
#define all(v) v.begin(),v.end()
#define fsp(x,y) fixed<<setprecision(y)<<x;
#define PI 3.1415926535897932384626433832795
#define MOD 1000000007 // (1e9+7)
#define pii pair<int,int>
#define pis pair<int,string>
#define vi vector<int>
#define vii vector<pii>
#define mii map<int,int>
//typedef long long int lli;
typedef long double ld;
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
void c_p_c()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
}
class Node {
public:
int data;
Node* next;
Node(int val) {
data = val;
next = 0 ;
}
};
void ll(Node **ref, int data) {
Node* nn = new Node(data);
// nn->data = data;
nn->next = (*ref);
*ref = nn;
return;
}
void display(Node *x) {
while (x != 0) {
cout << x->data << " ";
x = x->next;
}
return;
}
int lengthf(Node*head) {
int l = 0 ;
Node*temp = head ;
while (temp) {
temp = temp->next ;
l++;
}
return l ;
}
int intersection(Node*&head1, Node*&head2) {
int l1 = lengthf(head1);
int l2 = lengthf(head2);
int d = 0 ;
Node*p1 ;
Node*p2 ;
// now we must see which is the larger ll
// we traverse that first
// lets make p1 point the larger ll and p2 to the shorter one
if (l1 > l2) {
d = l1 - l2;
p1 = head1;
p2 = head2 ;
}
else {
d = l2 - l1;
p1 = head2;
p2 = head1;
}
// since p1 is pointing to larger ll, we traverse that only
while (d--) {
p1 = p1->next;
if (p1 == 0) {
return -1;
}
}
// now matching the address of the pointers and shifting them everytime...
while (p1 and p2) {
if (p1 == p2) {
return p1->data; // or even p2 data
}
p1 = p1->next;
p2 = p2->next;
}
return -1;
}
// say we have to intersect the ll... the function is :
void intersect(Node*&head1, Node*&head2, int pos) {
// if the length of ll1 is greater than ll2 ...
Node *temp1 = head1 ;
pos-- ; // we are starting count from 0...
while (pos--) {
temp1 = temp1->next;
}
Node *temp2 = head2 ;
while (temp2->next != NULL) {
temp2 = temp2->next ;
}
temp2->next = temp1;
}
////////////////////////
int32_t main() {
///////////
c_p_c();
///////////
// code
/*
int t ; cin >> t; while(t--){}
*/
Node *head1 = 0;
Node *head2 = 0;
int n1;
cin >> n1 ;
forn(i, n1) {
int data1;
cin >> data1;
ll(&head1, data1);
}
int n2;
cin >> n2 ;
forn(i, n2) {
int data2;
cin >> data2;
ll(&head2, data2);
}
display(head1);
ct("");
display(head2);
ct("");
intersect(head1, head2, 3);
ct(intersection(head1, head2));
return 0;
}