Codility – FrogRiverOne 문제 풀이 (난이도 : 하)

class Solution {
    public int solution(int X, int[] A) {
        // write your code in Java SE 8
        int leafList[] = new int[X+1];
        for(int i = 0 ; i < leafList.length ; i++){
            leafList[i] = -1;   
        }
        
        for(int i = 0 ; i < A.length ; i++){
            int leaf = A[i];
            if(leaf <= X ){
                if(leafList[leaf] == -1){
                    leafList[leaf] = i;
                }
                else{
                    leafList[leaf] = Math.min(i, leafList[leaf]);    
                }
            }
        }
        
        int result = 0;
        for(int i = 1 ; i < leafList.length ; i++){
            if(leafList[i] == -1){
                result = -1;
                break;
            }
            result = Math.max(result, leafList[i]);
        }
        
        return result;
    }
}

Codility – CountDiv 문제 풀이 (난이도 : 하)

// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int A, int B, int K) {
        // write your code in Java SE 8
        int result = B/K + 1;
        if(A != 0){
            result -= ((A-1)/K + 1);
        }
        return result;
    }
}

Codility – PassingCars 문제 풀이 (난이도 : 하)

// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        int toEast = 0;
        
        long pairCount = 0;
        
        for(int i = 0 ; i < A.length ; i++){
            if(A[i] == 0){
                toEast++; 
            } else{
                pairCount += toEast; 
            }
        }

        if(pairCount > 1000000000){
            return -1;   
        }
        
        return (int)pairCount;
    }
}

Codility – Missing Integer 문제 풀이 (난이도 : 하)

// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        
        boolean checker[] = new boolean[A.length + 1];
        
        for(int i = 0 ; i < A.length ; i++){
            int value = A[i];
            if(value > 0 && value < checker.length){
                checker[value] = true;
            }
        }
        
        for(int i = 1 ; i < checker.length ; i++){
            if(checker[i] == false){
                return i;   
            }
        }
        
        return checker.length;
    }
}

Codility – PermCheck 문제 풀이 (난이도 : 하)

// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        
        boolean checker[] = new boolean[A.length+1];
        
        for(int i = 0 ; i < A.length; i++){
            int value = A[i];
            if(value < checker.length){
                checker[value] = true;   
            }
        }
        
        int result = 1;
        for(int i = 1 ; i < checker.length ; i++){
            if(checker[i] == false){
                result = 0;
                break;
            }
        }
        
        return result;
    }
}

Codility – PermMissingElem 문제 풀이 (난이도 : 하)

// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        
        boolean occurred[] = new boolean[A.length + 2];
        
        for(int i = 0 ; i < A.length ; i++){
            int occurredNumber = A[i];
            occurred[occurredNumber] = true;
        }
        
        for(int i = 1 ; i < occurred.length ; i++){
            if(!occurred[i]){
                return i;
            }
        }
        
        return 0;
    }
}

Codility – FrogJmp 문제풀이 (난이도 : 하)

// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int X, int Y, int D) {
        // write your code in Java SE 8
        int distance = Y - X;
        return distance%D == 0 ? distance/D : distance/D + 1;
    }
}

Codility –  TapeEquilibrium 문제 풀이 (난이도 : 하)

// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        
        int front = 0;
        int back = 0;
        for(int i = 0 ; i < A.length ; i++){
            back += A[i];   
        }
        
        int minDiff = Integer.MAX_VALUE;
        int p = 1;
        for(int i = 1 ; i < A.length ; i++){
            front += A[i-1];
            back -= A[i-1];
            p = i;
            minDiff = Math.min(minDiff, Math.abs(front - back));
        }
        
        return minDiff;
        
    }
}

Codility – OddOccurrencesInArray 문제 풀이 (난이도 : 하)

// you can also use imports, for example:
// import java.util.*;
import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        HashMap<Integer, Boolean> pairedMap = new HashMap();

        for(int i = 0 ; i < A.length ; i++){
            int occurredNumber = A[i];
            Boolean paired = pairedMap.get(occurredNumber);
            if(paired == null || paired == true){
                pairedMap.put(occurredNumber, false);
            }
            else{
                pairedMap.put(occurredNumber, true);
            }
        }

        Iterator iterator = pairedMap.keySet().iterator();
        int minValue = Integer.MAX_VALUE;
        while(iterator.hasNext()){
            int key = iterator.next();
            Boolean paired = pairedMap.get(key);
            if(paired == false){
                minValue = Math.min(minValue, key);
            }
        }

        return minValue;
    }
}

Codility – CyclicRotation 문제 풀이 (난이도 : 하)

문제 유출은 안된다니 풀이만……

class Solution {
    public int[] solution(int[] A, int K) {
        // write your code in Java SE 8
        
        int[] a = new int[A.length];
        
        for(int i = 0 ; i < A.length ; i++){
            a[(i+K)%a.length] = A[i];
        }
        
        return a;
    }
}