From 236e1062b290e2d2345f1d1c319e78f15e0a311d Mon Sep 17 00:00:00 2001
From: zhaohongbo <zhaohbcloud@126.com>
Date: Fri, 7 Jun 2024 15:06:10 +0800
Subject: [PATCH] [CPU] Optimize the unique operator (#24850)

### Details:
 - *Optimize  unique using HashMap when sorted=false*
 - *...*

### Tickets:
 - *ticket-id*
---
 src/plugins/intel_cpu/src/nodes/unique.cpp | 40 ++++++++--------------
 1 file changed, 15 insertions(+), 25 deletions(-)

diff --git a/src/plugins/intel_cpu/src/nodes/unique.cpp b/src/plugins/intel_cpu/src/nodes/unique.cpp
index ad322756ab2..130213dfcb8 100644
--- a/src/plugins/intel_cpu/src/nodes/unique.cpp
+++ b/src/plugins/intel_cpu/src/nodes/unique.cpp
@@ -225,41 +225,31 @@ void Unique::flattenTensorExec() {
             }
         }
     } else {
-        uniDataTmpPtr[0] = srcDataPtr[0];
-        if (definedOutputs[FIRST_UNIQUE_IDX]) {
-            firstTmpPtr[0] = 0;
-        }
-        if (definedOutputs[INPUT_TO_UNIQ_IDX]) {
-            inToOutTmpPtr[0] = 0;
-        }
+        std::unordered_map<T, int32_t> uniq;
+        uniq.reserve(inputLen);
+
         if (definedOutputs[OCCURRENCES_NUM]) {
             std::fill(occurTmpPtr, occurTmpPtr + inputLen, 1);
         }
-        uniqueLen = 1;
 
-        for (size_t i = 1; i < inputLen; i++) {
-            bool found = false;
-            size_t j = 0;
-            for (; j < uniqueLen; j++) {
-                if (uniDataTmpPtr[j] == srcDataPtr[i]) {
-                    found = true;
-                    break;
-                }
-            }
-            if (!found) {
-                uniDataTmpPtr[uniqueLen] = srcDataPtr[i];
+        for (size_t i = 0, j = 0; i < inputLen; ++i) {
+            auto it = uniq.emplace(srcDataPtr[i], j);
+            inToOutTmpPtr[i] = it.first->second;
+            if (it.second) {
                 if (definedOutputs[FIRST_UNIQUE_IDX]) {
-                    firstTmpPtr[uniqueLen] = i;
+                    firstTmpPtr[j] = i;
                 }
-                uniqueLen++;
+                ++j;
             } else {
                 if (definedOutputs[OCCURRENCES_NUM]) {
-                    occurTmpPtr[j]++;
+                    occurTmpPtr[inToOutTmpPtr[i]]++;
                 }
             }
-            if (definedOutputs[INPUT_TO_UNIQ_IDX]) {
-                inToOutTmpPtr[i] = j;
-            }
+        }
+
+        uniqueLen = static_cast<int64_t>(uniq.size());
+        for (const auto& it : uniq) {
+            uniDataTmpPtr[it.second] = it.first;
         }
     }