[LeetCode/릿코드] 119. Pascal's Triangle II

문제

 

 

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풀이

 

 

 

import java.util.ArrayList;
import java.util.List;
class Solution {
    public List<Integer> getRow(int rowIndex) {
        List<Integer> first = new ArrayList<Integer>();
        first.add(1);
        
        List<Integer> second = new ArrayList<Integer>();
        second.add(1);
        second.add(1);
 
        if(rowIndex == 0) return first;
        if(rowIndex == 1) return second;
 
        List<Integer> previous = new ArrayList<Integer>();
        previous.add(1);
        previous.add(1);
        for(int i=2; i<=rowIndex+1; i++) {
            List<Integer> temp = new ArrayList<Integer>();
            for(int j=1; j<=i; j++) {
                if(j == 1 || j == i) {
                    temp.add(1);
                }else{
                    int n = previous.get(j-1-1) + previous.get(j-1);
                    temp.add(n);
                }
            }
            previous = temp;
        }
        return previous;
    }
}