diff --git a/src/apple.c b/src/apple.c
index 766d543..f9abf8e 100644
--- a/src/apple.c
+++ b/src/apple.c
@@ -4,6 +4,13 @@ int n;
 int k;
 int A[100000];
 
+int p(int x){
+  int sum = 0;
+ for(int i=0; i<n; i++){
+    sum = sum + (A[i]+x-1)/x; //切り上げ
+  }
+  return sum <= k; //kで持って帰れるなら1で持って帰れないなら0
+}
 
 int main(){
   int i, lb, ub;
@@ -12,6 +19,14 @@ int main(){
     scanf("%d", &A[i]);
   }
 
+  lb = 0;
+  ub = 1e9;
+  while(ub - lb > 1){
+    int mid = (lb + ub) / 2;
+    if( p(mid)) ub = mid;
+    else lb = mid;
+  }
 
+  printf("%d\n", ub);
   return 0;
-}
+  }
\ No newline at end of file
diff --git a/src/array.c b/src/array.c
index 13ed925..cae30b7 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;
-}
+}
\ No newline at end of file
diff --git a/src/spear.c b/src/spear.c
index 766d543..e67b550 100644
--- a/src/spear.c
+++ b/src/spear.c
@@ -5,6 +5,15 @@ int k;
 int A[100000];
 
 
+int sp(int l){
+  int sum=0;
+  for(int i=0; i<n; i++){
+    sum += A[i]/l;
+  }
+  if(sum>=k)return 0;
+  else return 1;
+}
+
 int main(){
   int i, lb, ub;
   scanf("%d%d", &n, &k);
@@ -12,6 +21,14 @@ int main(){
     scanf("%d", &A[i]);
   }
 
+  lb = 0;
+  ub = 1e9 + 1;
+  while(ub - lb > 1){
+    int mid = (lb + ub) / 2;
+    if(sp((mid))) ub = mid;
+    else lb = mid;
+  }
 
+  printf("%d\n", lb);
   return 0;
 }
diff --git a/src/works.c b/src/works.c
index 766d543..b587da8 100644
--- a/src/works.c
+++ b/src/works.c
@@ -4,6 +4,23 @@ int n;
 int k;
 int A[100000];
 
+int wr(int x){
+  int worker = 1;
+  int work = 0;
+  for(int i = 0; i < n; i++ ){   
+    if(work + A[i] <= x){
+      work = work + A[i];  
+    }
+    else if(A[i] <= x){
+      work=A[i];
+      worker++;
+    }
+    else{
+      return 0;
+    }
+  }
+  return worker <= k;  
+}
 
 int main(){
   int i, lb, ub;
@@ -12,6 +29,14 @@ int main(){
     scanf("%d", &A[i]);
   }
 
+  lb = 0;
+  ub = 1e9;
+  while(ub - lb > 1){
+    int mid = (lb + ub) / 2;
+    if(wr((mid))) ub = mid;
+    else lb = mid;
+  }
 
+  printf("%d\n", ub);
   return 0;
 }