Since there is no duplicate, we can create a `valToIndex`

map to accelerate lookup for the index we need to start from.

```
public class Solution {
public int[] nextGreaterElement(int[] findNums, int[] nums) {
Map<Integer, Integer> valToIndex = new HashMap<>();
for (int i = 0; i < nums.length; i++) {
valToIndex.put(nums[i], i);
}
int[] result = new int[findNums.length];
for (int i = 0; i < findNums.length; i++) {
result[i] = -1;
int start = valToIndex.get(findNums[i]);
for (int j = start + 1; j < nums.length; j++) {
if (nums[j] > findNums[i]) {
result[i] = nums[j];
break;
}
}
}
return result;
}
}
```