verify/yosupo-longest_increasing_subsequence-longest_increasing_subsequence.test.cpp

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• Last update: 2025-07-03 00:41:25+09:00
• Problem: https://judge.yosupo.jp/problem/longest_increasing_subsequence
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Depends on

• Longest Increasing Subsequence（最長増加部分列） (algorithm/Others/longest_increasing_subsequence.hpp)

Code

#define PROBLEM "https://judge.yosupo.jp/problem/longest_increasing_subsequence"

#include <algorithm>
#include <iostream>
#include <vector>

#include "../algorithm/Others/longest_increasing_subsequence.hpp"

int main() {
    int n;
    std::cin >> n;

    std::vector<int> a(n);
    for(auto &in : a) std::cin >> in;

    auto &&dp = algorithm::lis(a);
    auto itr = std::max_element(dp.begin(), dp.end()) - dp.begin();

    std::vector<int> ans;
    ans.push_back(itr);
    for(int i = itr - 1; i >= 0; --i) {
        if(dp[i] == dp[ans.back()] - 1) ans.push_back(i);
    }
    std::reverse(ans.begin(), ans.end());

    std::cout << ans.size() << "\n";
    for(auto elem : ans) std::cout << elem << " ";
    std::cout << std::endl;
}

#line 1 "verify/yosupo-longest_increasing_subsequence-longest_increasing_subsequence.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/longest_increasing_subsequence"

#include <algorithm>
#include <iostream>
#include <vector>

#line 1 "algorithm/Others/longest_increasing_subsequence.hpp"



/**
 * @brief Longest Increasing Subsequence（最長増加部分列）
 * @docs docs/Others/longest_increasing_subsequence.md
 */

#line 10 "algorithm/Others/longest_increasing_subsequence.hpp"
#include <functional>
#line 12 "algorithm/Others/longest_increasing_subsequence.hpp"

namespace algorithm {

// 最長増加部分列 (LIS: Longest Increasing Subsequence) の長さを求める．O(N*logN).
template <typename Type, class Compare = std::function<bool(const Type &, const Type &)> >
std::vector<int> lis(const std::vector<Type> &v, Compare comp = [](const Type &a, const Type &b) -> bool { return a < b; }) {
    const int n = v.size();
    std::vector<int> res(n, 0);  // res[i]:=(v[i]を最後の要素とする最長増加部分列の長さ).
    std::vector<Type> dp;        // dp[k]:=(長さkの増加部分列のうち，その最後の要素の最小値).
    for(int i = 0; i < n; ++i) {
        auto itr = std::lower_bound(dp.begin(), dp.end(), v[i], comp);
        res[i] = itr - dp.begin() + 1;
        if(itr == dp.end()) dp.push_back(v[i]);
        else *itr = v[i];
    }
    return res;
}

// 最長増加部分列 (LIS: Longest Increasing Subsequence) の長さを求める．O(N*logN).
template <typename Type, class Compare = std::function<bool(const Type &, const Type &)> >
std::vector<int> lis2(const std::vector<Type> &v, Compare comp = [](const Type &a, const Type &b) -> bool { return a < b; }) {
    const int n = v.size();
    std::vector<int> res(n + 1, 0);  // res[i]:=(v[:i]における最長増加部分列の長さ).
    std::vector<Type> dp;            // dp[k]:=(長さkの増加部分列のうち，その最後の要素の最小値).
    for(int i = 0; i < n; ++i) {
        auto itr = std::lower_bound(dp.begin(), dp.end(), v[i], comp);
        if(itr == dp.end()) dp.push_back(v[i]);
        else *itr = v[i];
        res[i + 1] = dp.size();
    }
    return res;
}

}  // namespace algorithm


#line 8 "verify/yosupo-longest_increasing_subsequence-longest_increasing_subsequence.test.cpp"

int main() {
    int n;
    std::cin >> n;

    std::vector<int> a(n);
    for(auto &in : a) std::cin >> in;

    auto &&dp = algorithm::lis(a);
    auto itr = std::max_element(dp.begin(), dp.end()) - dp.begin();

    std::vector<int> ans;
    ans.push_back(itr);
    for(int i = itr - 1; i >= 0; --i) {
        if(dp[i] == dp[ans.back()] - 1) ans.push_back(i);
    }
    std::reverse(ans.begin(), ans.end());

    std::cout << ans.size() << "\n";
    for(auto elem : ans) std::cout << elem << " ";
    std::cout << std::endl;
}

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