Alice and Bob like games. And now they are ready to start a new game. They have placed n chocolate bars in a line. Alice starts to eat chocolate bars one by one from left to right, and Bob — from right to left. For each chocololate bar the time, needed for the player to consume it, is known (Alice and Bob eat them with equal speed). When the pla…

Codeforces6C.java

/**
 * Problem Link: http://codeforces.com/problemset/problem/6/C
 * Alice = getDivideIndex(..)+1;
 * Bob = arrayLength - Alice; 
 */
public class Codeforces6C {
	private static int getDivideIndexRec(int[] arr, int i, int j, boolean isLeft){
		if(i==j){
			if(isLeft) return i-1;
			else return i;
		}
		if(arr[i]<arr[j]){
			arr[j]-=arr[i];
			return getDivideIndexRec(arr,i+1,j,true);
		}
		else if(arr[i]>arr[j]){
			arr[i]-=arr[j];
			return getDivideIndexRec(arr,i,j-1,false);
		}
		else{
			return getDivideIndexRec(arr,i+1,j-1,false);
		}
	}
	public static int getDivideIndex(int[] arr){
		if(arr.length<1) return -1;//error
		return getDivideIndexRec(arr,0,arr.length-1,false);
	}
}

Codeforces6CTest.java

public class Codeforces6CTest {
	@Test
	public void testGetDivideIndex() {
		assertEquals(1,Codeforces6C.getDivideIndex(new int[]{2,9,8,2,7}));
		assertEquals(0,Codeforces6C.getDivideIndex(new int[]{2}));
		assertEquals(2,Codeforces6C.getDivideIndex(new int[]{2,2,2,2,2}));
	}
}