백준 2343

package baekjoon.이분탐색;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

class Main2343 {

   static int N, M;
   static int[] A, tmp;

   public static void main(String[] args) throws Exception {
      input();
      go();
   }

   private static void go() {
      int L = A[1], R = 1_000_000_000, ans = 0;
      for (int i = 1; i <= N; i++)
         L = Math.max(L, A[i]);

      while (L <= R) {
         int mid = (L + R) / 2;
         if (determination(mid)) {
            ans = mid;
            R = mid - 1;
         } else {
            L = mid + 1;
         }
      }
      System.out.println(ans);
   }

   private static boolean determination(int mid) {
      int cnt = 1, sum = 0;
      for (int i = 1; i <= N; i++) {
         if (sum + A[i] > mid) {
            cnt++;
            sum = A[i];
         } else {
            sum += A[i];
         }
      }
      return cnt <= M;
   }

   private static void input() throws IOException {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      N = Integer.parseInt(st.nextToken());
      M = Integer.parseInt(st.nextToken());
      A = new int[N + 1];
      tmp = new int[N + 1];
      st = new StringTokenizer(br.readLine());
      for (int i = 1; i <= N; i++) {
         A[i] = Integer.parseInt(st.nextToken());
         tmp[i] = tmp[i - 1] + A[i];
      }
   }
}