diff --git a/src/apple.c b/src/apple.c
index 766d543..9f1d555 100644
--- a/src/apple.c
+++ b/src/apple.c
@@ -4,6 +4,7 @@ int n;
 int k;
 int A[100000];
 
+int p(int bag_accept);
 
 int main(){
   int i, lb, ub;
@@ -12,6 +13,31 @@ int main(){
     scanf("%d", &A[i]);
   }
 
+  lb = 0;
+  ub = 1000000000;
+  while(ub - lb > 1){
+    int mid = (lb + ub) / 2;
+    if(p(mid)){
+      ub = mid;
+    }
+    else{
+      lb = mid;
+    }
+  }
+
+  printf("%d\n", ub);
 
   return 0;
 }
+
+int p(int bag_accept){
+  int i, bag_sum;
+
+  bag_sum = 0;
+  for(i = 0; i < n; i++){
+    bag_sum += (A[i] + bag_accept - 1) / bag_accept;
+  }
+
+  if(bag_sum <= k) return 1;
+  else return 0;
+}
\ No newline at end of file
diff --git a/src/array.c b/src/array.c
index 13ed925..0ca439c 100644
--- a/src/array.c
+++ b/src/array.c
@@ -12,7 +12,15 @@ int main(){
     scanf("%d", &A[i]);
   }
 
+  lb = -1;
+  ub = n;
+  while(ub - lb > 1){
+    int mid = (lb + ub) / 2;
+    if(A[mid] >= k) ub = mid;
+    else lb = mid;
+  }
 
+  printf("%d\n", ub);
 
   return 0;
 }
diff --git a/src/spear.c b/src/spear.c
index 766d543..19a2c2b 100644
--- a/src/spear.c
+++ b/src/spear.c
@@ -4,6 +4,7 @@ int n;
 int k;
 int A[100000];
 
+int p(int spear_length);
 
 int main(){
   int i, lb, ub;
@@ -12,6 +13,31 @@ int main(){
     scanf("%d", &A[i]);
   }
 
+  lb = 0;
+  ub = 1000000001;
+  while(ub - lb > 1){
+    int mid = (lb + ub) / 2;
+    if(p(mid)){
+      lb = mid;
+    }
+    else{
+      ub = mid;
+    }
+  }
+
+  printf("%d\n", lb);
 
   return 0;
 }
+
+int p(int spear_length){
+  int spear_num = 0;
+  int i;
+
+  for(i = 0; i < n; i++){
+    spear_num += A[i] / spear_length;
+  }
+  
+  if(spear_num >= k) return 1;
+  else return 0;
+}
\ No newline at end of file