Submission #1283207

#	Time	Username	Problem	Language	Result	Execution time	Memory
1283207		abc123	Bit Shift Registers (IOI21_registers)	C++20	Compilation error	0 ms	0 KiB

registers

#include <bits/stdc++.h>
using namespace std;

// Function declarations provided by grader
void append_move(int t, int y);
void append_store(int t, vector<int> v);
void append_and(int t, int x, int y);
void append_or(int t, int x, int y);
void append_xor(int t, int x, int y);
void append_not(int t, int x);
void append_left(int t, int x, int p);
void append_right(int t, int x, int p);
void append_add(int t, int x, int y);

// THIS is what you implement:
void construct_instructions(int n, int k, int q, int w) {
    // n = number of integers
    // k = bits per integer  
    // q = max operations
    // w = total bits (2000)
    
    // Step 1: Load numbers into separate registers
    // Input: r[0] contains all n numbers packed as bits [0:k), [k:2k), ...
    
    for(int i = 0; i < n; i++) {
        if(i > 0) {
            append_right(10 + i, 0, i * k);  // Extract i-th number
        }
    }
    
    // Step 2: Bubble sort using bitwise comparison
    for(int i = 0; i < n && i < q; i++) {
        for(int j = 0; j < n - i - 1 && j + i < q; j++) {
            int idx1 = (i == 0) ? 0 : (10 + j);
            int idx2 = (j == 0 && i == 0) ? 1 : (10 + j + 1);
            int temp = 20 + j;
            
            // Compare: if r[idx1] > r[idx2], swap
            // Use XOR to compute if different: a XOR b = 0 if equal
            append_xor(temp, idx1, idx2);
            
            // For actual comparison, use: subtract and check sign
            // diff = a - b
            append_not(temp + 1, idx2);
            append_add(temp + 1, idx1, temp + 1);
            append_add(temp + 1, temp + 1, 1);
            
            // If diff is negative (top bit set), then idx1 < idx2 (already in order)
            // If diff is positive, swap needed
            append_right(temp + 2, temp + 1, k - 1);  // Extract sign bit
        }
    }
    
    // Step 3: Reconstruct sorted array into r[0]
    append_store(0, vector<int>(n)); // Store all zeros first
    for(int i = 0; i < n; i++) {
        int src = (i == 0) ? 0 : (10 + i);
        append_left(0, src, i * k);  // Reconstruct into r[0]
    }
}

Compilation message (stderr)

/usr/bin/ld: /tmp/cc2S9Bum.o: in function `construct_instructions(int, int, int, int)':
registers.cpp:(.text+0x1be): undefined reference to `append_store(int, std::vector<int, std::allocator<int> >)'
collect2: error: ld returned 1 exit status