{"id":28323169,"url":"https://github.com/lzyrapx/notes","last_synced_at":"2026-03-03T16:09:44.422Z","repository":{"id":192773388,"uuid":"141291226","full_name":"lzyrapx/Notes","owner":"lzyrapx","description":"👍Some notes...","archived":false,"fork":false,"pushed_at":"2019-10-21T12:43:15.000Z","size":18725,"stargazers_count":12,"open_issues_count":0,"forks_count":7,"subscribers_count":2,"default_branch":"master","last_synced_at":"2025-06-15T10:51:40.022Z","etag":null,"topics":["notes","sb-admin"],"latest_commit_sha":null,"homepage":"","language":"C++","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/lzyrapx.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null}},"created_at":"2018-07-17T13:08:35.000Z","updated_at":"2024-02-17T21:28:34.000Z","dependencies_parsed_at":null,"dependency_job_id":"b0a20ddb-b94e-4e98-896f-d13f1d66d2c6","html_url":"https://github.com/lzyrapx/Notes","commit_stats":null,"previous_names":["lzyrapx/notes"],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/lzyrapx/Notes","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/lzyrapx%2FNotes","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/lzyrapx%2FNotes/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/lzyrapx%2FNotes/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/lzyrapx%2FNotes/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/lzyrapx","download_url":"https://codeload.github.com/lzyrapx/Notes/tar.gz/refs/heads/master","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/lzyrapx%2FNotes/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":30051207,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-03-03T15:26:47.567Z","status":"ssl_error","status_checked_at":"2026-03-03T15:26:17.132Z","response_time":61,"last_error":"SSL_connect returned=1 errno=0 peeraddr=140.82.121.5:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["notes","sb-admin"],"created_at":"2025-05-25T15:11:03.640Z","updated_at":"2026-03-03T16:09:44.393Z","avatar_url":"https://github.com/lzyrapx.png","language":"C++","funding_links":[],"categories":[],"sub_categories":[],"readme":"# 这是一些笔记.(This is my notes)\n***\n## Example:\n## Notes\n### 理性分析 C++(-O2) 和 JS 的性能差距.\n### On Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz.\n### Test1：\n#### 最后一行：时间(ms)\n```\n#pragma GCC optimize(\"O2\")\n#include \u003cbits/stdc++.h\u003e\nusing namespace std;\nint main(int argc, char const *argv[]) {\n  int t = clock();\n  int a = 1000000000,b = 1;\n   while(a) {\n     b \u003c\u003c= 1;\n     a--;\n   }\n  printf(\"%d ms\\n\",clock() - t);\n  return 0;\n}\n\n// 0 ms\n```\n\n```\nvar t;\nt = new Date;\nvar a = 1000000000,\n    b = 1;\nwhile(a) {\n    b \u003c\u003c= 1;\n    a--;\n}\nconsole.log(new Date - t + \"ms\");\n\n// 915ms\n```\n### Test2：\n```\n#pragma GCC optimize(\"O2\")\n#include \u003cbits/stdc++.h\u003e\nusing namespace std;\nint a[10000100];\nvoid quick_sort(int a[], int l, int r) {\n    if (l \u003c r) {\n        int i = l, j = r, x = a[l];\n        while (i \u003c j) {\n            while(i \u003c j \u0026\u0026 a[j] \u003e= x) j--;\n            if(i \u003c j) a[i++] = a[j];\n            while(i \u003c j \u0026\u0026 a[i] \u003c x) i++;\n            if(i \u003c j) a[j--] = a[i];\n        }\n        a[i] = x;\n        quick_sort(a, l, i - 1);\n        quick_sort(a, i + 1, r);\n    }\n}\nint main(int argc, char const *argv[]) {\n  srand((int)time(0));\n  for(int i = 0;i \u003c 10000000; i++) {\n    a[i] = rand();\n  }\n  int t = clock();\n  quick_sort(a,0,10000000);\n  printf(\"%d ms\\n\",clock() -t);\n  return 0;\n}\n\n// 1738 ms\n```\n```\nfunction quick_sort(a,l,r) {\n    if (l \u003c r) {\n        var i = l, j = r, x = a[l];\n        while (i \u003c j) {\n            while(i \u003c j \u0026\u0026 a[j] \u003e= x) j--;\n            if(i \u003c j) a[i++] = a[j];\n            while(i \u003c j \u0026\u0026 a[i] \u003c x) i++;\n            if(i \u003c j) a[j--] = a[i];\n        }\n        a[i] = x;\n        quick_sort(a, l, i - 1);\n        quick_sort(a, i + 1, r);\n    }\n}\nvar s,i,t;\nfor(i=0,s=[];i\u003c10000000;i++) s.push(Math.random()*1E7|0);\nt = new Date;\nquick_sort(s,0,10000000);\nconsole.log(new Date - t + \" ms\");\n\n// 3080 ms\n```\n### Test3：\n```\n#pragma GCC optimize(\"O2\")\n#include \u003cbits/stdc++.h\u003e\nusing namespace std;\nconst int maxn = 50000000;\nint a[maxn];\nint p[maxn],m[maxn];\nint pc;\nint main(int argc, char const *argv[]) {\n  int t = clock();\n  for(int i = 2; i \u003c maxn; i++) {\n    if(m[i] == 0) {\n      p[++pc] = m[i] = i;\n    }\n    int k = 0;\n    for(int j = 1; j \u003c= pc \u0026\u0026 p[j] \u003c= m[i] \u0026\u0026 (k = p[j] * i) \u003c maxn; j++) {\n      m[k] = p[j];\n    }\n  }\n  int ans = 0;\n  for(int i = 1; i \u003c= pc; i++) {\n    ans ^= p[i];\n  }\n  printf(\"%d\\n\", ans);\n  printf(\"%d ms\\n\",clock() - t);\n  return 0;\n}\n\n// 338 ms\n```\n```\nvar pc = 0;\n\nvar m = [];\nvar p = [];\nfunction solve() {\n    // console.log(\"ok\");\n    var i;\n    for(i = 2 ;i \u003c 50000000;i++) {\n        if(m[i] == null) {\n            // console.log(i);\n            p[++pc]  = m[i] = i;\n        }\n        var k = 0;\n        var j ;\n        for(j = 1; j \u003c= pc \u0026\u0026 p[j] \u003c= m[i] \u0026\u0026 (k = p[j] * i) \u003c 50000000; j++) {\n            m[k] = p[j];\n        }\n    }\n    // console.log(\"pc = \" + pc);\n    var ans = 0;\n    for(var i = 1; i \u003c= pc; i++) {\n        ans ^= p[i];\n    }\n    console.log(\"ans= \" +  ans);\n}\nt = new Date;\nsolve();\nconsole.log(new Date - t + \" ms\");\n\n// 8096 ms\n\n```\n### Test4：\n```\n#pragma GCC optimize(\"O2\")\n#include \u003cbits/stdc++.h\u003e\nusing namespace std;\nconst int maxn = 1000;\n\nint G[1000][1000];\nint sed = 0;\ninline int getRand()\n{\n  return sed = (sed * sed * 73 + sed * 233 + 19260817) \u0026 0x0000ffff;\n}\nint main(int argc, char const *argv[]) {\n  int t = clock();\n  for(int i = 0; i \u003c maxn; i++) {\n    for(int j = 0; j \u003c maxn; j++) {\n      G[i][j] = getRand();\n    }\n  }\n  for(int i = 0; i \u003c maxn; i++) {\n    for(int j = 0; j \u003c maxn; j++) {\n      for(int k = 0; k \u003c maxn; k++) {\n        if(G[j][k] \u003e G[j][i] + G[i][k]) {\n          G[j][k] = G[j][i] + G[i][k];\n        }\n      }\n    }\n  }\n  int ans = 0;\n  for(int i = 0; i \u003c maxn; i++) {\n    for(int j = 0; j \u003c maxn; j++) {\n      ans ^= G[i][j];\n    }\n  }\n  printf(\"%d\\n\", ans);\n  printf(\"%d ms\\n\",clock() - t);\n  return 0;\n}\n\n// 1718 ms\n```\n```\nvar sed = 0;\nvar G = new Array();\nfunction getRand() {\n    var res = sed = (sed * sed * 73 + sed * 233 + 19260817) \u0026 0x0000ffff;\n    // console.log(\"res = \" +  res);\n    return res;\n}\nfunction solve() {\n    // console.log(\"ok\");\n    for(var i = 0; i \u003c 1000; i++) {\n        G[i] = new Array();\n        for(var j = 0; j \u003c 1000; j++) {\n            G[i][j]  = getRand();\n        }\n    }\n    for(var i = 0; i \u003c 1000; i++) {\n        for(var j = 0; j \u003c 1000; j++) {\n            for(var k = 0; k \u003c 1000; k++) {\n                if(G[j][k] \u003e G[j][i] + G[i][k]) {\n                    G[j][k] = G[j][i] + G[i][k];\n                }\n            }\n        }\n    }\n    var ans = 0;\n    for(var i = 0; i \u003c 1000; i++) {\n        for(var j = 0; j \u003c 1000; j++) {\n            ans ^= G[i][j];\n        }\n    }\n    console.log(\"ans= \" +  ans);\n}\nt = new Date;\nsolve();\nconsole.log(new Date - t + \" ms\");\n\n// 3440 ms\n\n```\n### Test5：\n```\n#pragma GCC optimize(\"O2\")\n#include \u003cbits/stdc++.h\u003e\nusing namespace std;\nconst int maxn = 1000000000; // 1e9\ntypedef unsigned long long ull;\nint P = 1000000007;\n\nint main(int argc, char const *argv[]) {\n  int t = clock();\n  ull ans = 1;\n  for(int i = 1; i \u003c maxn; i++) {\n    ans = ans * i % P;\n  }\n  printf(\"%llu\\n\",ans);\n  printf(\"%d ms\\n\",clock() - t);\n  return 0;\n}\n\n// 11953 ms\n```\n```\nvar P = 1000000007;\nvar maxn = 1000000000;// 1e9\nfunction solve() {\n    // console.log(\"ok\");\n    var ans =  1;\n    for(var i = 1; i \u003c maxn; i++) {\n        ans = ans * i % P;\n    }\n    console.log(\"ans= \" +  ans);\n}\nt = new Date;\nsolve();\nconsole.log(new Date - t + \" ms\");\n\n// 32175 ms\n```\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Flzyrapx%2Fnotes","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Flzyrapx%2Fnotes","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Flzyrapx%2Fnotes/lists"}