Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, ...

Assume that there is only one duplicate number, find the duplicate ... Setin both Python and Java rely on underlying hash tables, so insertion and lookup have amortized constant time complexities. The ...

We do scan the unique items list for each entry in the main list, but even in a worst case this greatly reduces the number of comparisons. Those two examples let us check for duplicates. The improved ...