add junior codes from rontogiannis

2020/AGRCOWS.cpp

+#include <stdio.h>
+#include <algorithm>
+
+using namespace std;
+
+const int MAXN = 100005;
+
+int stalls[MAXN];
+
+bool check_d(int N, int C, int d) {
+	int remaining_cows = C;
+	int current_stall = 0;
+	int previous_stall = -1;
+
+	while(remaining_cows > 0 && current_stall < N) {
+		if(previous_stall == -1) {
+			remaining_cows--;
+			previous_stall = current_stall;
+			current_stall++;
+		}
+		else {
+			if(stalls[current_stall] - stalls[previous_stall] >= d) {
+				remaining_cows--; // place a cow on current_stall
+				previous_stall = current_stall;
+				current_stall++;
+			} else {
+				current_stall++; // cannot add cow; move to next stall
+			}
+		}
+	}
+
+	if(remaining_cows == 0) return true;
+	else return false;
+}
+
+int main() {
+	int T;
+	scanf("%d", &T);
+
+	while(T--) {
+		int N, C;
+		scanf("%d %d", &N, &C);
+
+		for(int i=0; i<N; ++i) 
+			scanf("%d", stalls+i);
+
+		sort(stalls, stalls+N);
+
+		int lo = 0, hi = stalls[N-1]-stalls[0], result = 0;
+
+		while(lo <= hi) {
+			int mid = (lo+hi)/2;
+
+			if(check_d(N, C, mid) == true) {
+				lo = mid+1;
+				result = mid;
+			}
+			else hi = mid - 1;
+		}
+
+		printf("%d\n", result);
+	}
+
+	return 0;
+}
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2020/BSEARCH.cpp

+#include <stdio.h>
+
+const int MAXN = 100005;
+
+int A[MAXN+1];
+
+int bsearch(int lo, int hi, int key) {
+	if(lo == hi) {
+		if(A[lo] == key) return lo;
+		else return -1;
+	}
+
+	int mid = (lo+hi)/2;
+
+	if(A[mid] < key) {
+		lo = mid+1;
+		return bsearch(lo, hi, key);
+	}
+	else if(A[mid] > key) {
+		hi = mid-1;
+		return bsearch(lo, hi, key);
+	}
+	else return mid;
+}
+
+int bsearch_iterative(int N, int key) {
+	int lo = 0, hi = N-1;
+
+	while(lo < hi) {
+		int mid = (lo+hi)/2;
+
+		if(A[mid] < key) lo = mid+1; // continue on the right half
+		else if(A[mid] > key) hi = mid-1; // continue on the left half
+		else return mid;
+	}
+
+	if(A[lo] == key) return lo;
+	else return -1;
+}
+
+int main() {
+	int N, key;
+	scanf("%d %d", &N, &key);
+
+	for(int i=0; i<N; ++i) {
+		scanf("%d", A+i);
+	}
+
+	printf("%d\n", bsearch(0, N-1, key));
+	printf("%d\n", bsearch_iterative(N, key));
+
+}
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