O(1) space solution using two pointers

  • 0
        public int findLength(int[] A, int[] B) {
            int i=0, j=0, maxLeng=0;  
            while (j<A.length){
                while (j<A.length && isSub(A, i, j+1, B)){
                maxLeng = Math.max(maxLeng, j-i); 
                while (i<j && !isSub(A, i, j, B)){
            return maxLeng; 
        public boolean isSub(int[] A, int s, int e, int[] B){
            if (s>=e) return true; 
            if (e>A.length) e=A.length; 
            for (int i=0; i<=B.length-e+s; i++){
                int j=s; 
                for (; j<e; j++){
                    if (A[j]!=B[i+j-s]) break; 
                if (j==e) return true; 
            return false; 

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