(This question has been seen in the interviews of the following companies: Google)

Given two two integer arrays. Find the longest common subsequence.

eg: a =[1 5 2 6 3 7], b = [5 6 7 1 2 3]. return [1 2 3] or [5 6 7]

Solution:

```
static int[] maxLCS(int[] a, int[] b) {
int[][] op = new int[a.length + 1][b.length + 1];
for(int i = 1; i < a.length + 1; i++) {
for(int j = 1 ;j < b.length + 1; j++) {
if(a[i-1] == b[j-1]){
op[i][j] = op[i-1][j-1] + 1;
}else {
op[i][j] = Math.max(op[i-1][j], op[i][j-1]);
}
}
}
int maxLen = op[a.length][b.length];
int[] result = new int[maxLen];
int ap = a.length;
int bp = b.length;
while(ap > 0 && bp > 0) {
if(a[ap-1] == b[bp-1]) {
result[maxLen-1] = a[ap-1];
maxLen--;
ap--;
bp--;
}else if(op[ap-1][bp] <= op[ap][bp-1]) {
bp--;
}else {
ap--;
}
}
return result;
}
```

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