52 lines
1.1 KiB
Java
52 lines
1.1 KiB
Java
package simple2;
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import test.Test;
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// @NotThreadSafe
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public class SingleUpdatePerThread {
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private static long result;
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private SingleUpdatePerThread() {
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// Cannot be instantiated
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}
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private static void addPartialResult(long partial) {
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result += partial;
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}
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public static long sum(int[] nums) throws Exception {
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result = 0;
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Thread[] threads = new Thread[Test.NUM_THREADS];
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int size = (int) Math.ceil((double) nums.length / Test.NUM_THREADS);
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for (int i = 0; i < Test.NUM_THREADS; i++) {
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threads[i] = new Thread(
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new SumSingleUpdate(nums, i * size, (i + 1) * size));
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threads[i].start();
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}
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for (Thread thread : threads) {
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thread.join();
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}
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return result;
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}
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static class SumSingleUpdate implements Runnable {
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private final int[] nums;
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private final int low;
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private final int high;
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public SumSingleUpdate(int[] nums, int low, int high) {
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this.nums = nums;
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this.low = low;
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this.high = Math.min(high, nums.length);
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}
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public void run() {
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long partialSum = 0;
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for (int i = low; i < high; i++) {
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partialSum += nums[i];
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}
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SingleUpdatePerThread.addPartialResult(partialSum);
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}
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}
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}
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