三种写法算得一样吗

暴力、记忆化、填表三种写法，同一批物品、同一个容量。运行下面这段程序：

#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
using namespace std;
using Item = pair<int, int>;   // (重量, 价值)

const vector<Item> ITEMS = {{3, 8}, {4, 9}, {5, 11}};

const vector<Item> IT = {{1, 1}, {2, 3}, {1, 2}, {2, 2}, {1, 1}, {2, 4}, {1, 3}, {2, 2}, {1, 1}, {2, 3}};
long long calls = 0;

int go_rec(int i, int c) {
    calls++;
    if (i == (int)IT.size()) return 0;
    auto [w, v] = IT[i];
    int best = go_rec(i + 1, c);
    if (c >= w) {
        int take = go_rec(i + 1, c - w) + v;
        if (take > best) best = take;
    }
    return best;
}

vector<vector<int>> memo;

int go_memo(int i, int c) {
    calls++;
    if (memo[i][c] != -1) return memo[i][c];
    if (i == (int)IT.size()) return 0;
    auto [w, v] = IT[i];
    int best = go_memo(i + 1, c);
    if (c >= w) {
        int take = go_memo(i + 1, c - w) + v;
        if (take > best) best = take;
    }
    memo[i][c] = best;
    return best;
}

vector<long long> knap1d(const vector<Item>& items, int cap) {
    vector<long long> dp(cap + 1, 0);
    for (auto [w, v] : items) {
        for (int c = cap; c >= w; c--) {
            if (dp[c - w] + v > dp[c]) dp[c] = dp[c - w] + v;
        }
    }
    return dp;
}

int main() {
    int a = go_rec(0, 8);
    memo.assign(IT.size() + 1, vector<int>(9, -1));
    int b = go_memo(0, 8);
    cout << a << "/" << b << "/" << knap1d(IT, 8)[8] << endl;
}

（本题用 g++ -std=c++17 -O0 编译。）