java: add «1894. Find the Student that Will Replace the Chalk»

Signed-off-by: Matej Focko <me@mfocko.xyz>

java/find-the-student-that-will-replace-the-chalk.java

@@ -0,0 +1,31 @@
+class Solution {
+  private long getSum(int[] chalk, int k) {
+    long sum = 0;
+
+    for (int uses : chalk) {
+      sum += uses;
+      if (sum > k) {
+        break;
+      }
+    }
+
+    return sum;
+  }
+
+  public int chalkReplacer(int[] chalk, int k) {
+    var partialSum = getSum(chalk, k);
+
+    // Remove whole iterations over the students
+    k %= partialSum;
+
+    for (int i = 0; i < chalk.length; ++i) {
+      if (k < chalk[i]) {
+        return i;
+      }
+
+      k -= chalk[i];
+    }
+
+    return 0;
+  }
+}