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142 lines
2.9 KiB
142 lines
2.9 KiB
#include <stdint.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include "map.h"
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typedef uint64_t u64;
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#ifdef TEST
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#define PREAMBLE 5
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#else
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#define PREAMBLE 25
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#endif
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#define input_sz (sizeof(input) / sizeof(u64))
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const u64 input[] = {
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#ifdef TEST
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#include "input-test.h"
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#else
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#include "input.h"
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#endif
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};
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#define box(t) (calloc(sizeof(t), 1))
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struct pair {
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bool valid;
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u64 num;
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u64 sum[2];
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};
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inline static void insert_page(map_t* restrict where, u64 key, size_t i)
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{
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//if(key > PAGE_SIZE) panic("Data too large, increase page size to fit %lu in a single page", key);
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map_insert(where, key, i);
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}
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static void calculate_deficits(const u64 pre[static PREAMBLE], map_t * restrict output, u64 target)
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{
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for(size_t i=0;i<PREAMBLE;i++)
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if(target > pre[i])
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insert_page(output, target - pre[i], i);
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}
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#ifdef PART2
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static u64 csum(size_t i, size_t j)
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{
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register u64 sum=0;
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for(;i<=j;i++)
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sum += input[i];
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return sum;
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}
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static void reduce_bound(size_t* restrict i, size_t* restrict j, bool ex_by_high)
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{
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register u64 ibound = 0; int iset=0;
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register u64 jbound = 0; int jset=0;
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if(*i<input_sz) (iset = 1, ibound = input[*i+1]);
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if(*j!=0) (jset = -1, jbound = input[*j-1]);
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if(ex_by_high)
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*(ibound>jbound ? i : j) += (ibound>jbound ? iset : jset);
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else
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*(ibound<jbound ? i : j) += (ibound<jbound ? iset: jset);
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}
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static void extend_bound(size_t* restrict i, size_t* restrict j, bool ex_by_high)
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{
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register u64 ibound = 0; int iset=0;
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register u64 jbound = 0; int jset=0;
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if(*i!=0) (iset = -1, ibound = input[*i-1]);
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if(*j<input_sz) (jset = 1, jbound = input[*j+1]);
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if(ex_by_high)
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*(ibound>jbound ? i : j) += (ibound>jbound ? iset : jset);
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else
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*(ibound<jbound ? i : j) += (ibound<jbound ? iset: jset);
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}
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static u64 find_set(u64 target)
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{
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size_t i=0,j=0;
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while(1)
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{
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u64 sum = csum(i,j);
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if(sum == target) {
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printf("%lu\n", input[i] + input[j]);
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return 0;
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}
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else if(sum < target) {
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extend_bound(&i, &j, true);
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} else if(sum > target) {
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reduce_bound(&i, &j, true);
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}
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}
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fprintf(stderr, "No set found\n");
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return 1;
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}
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#endif
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int main()
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{
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map_t def = map_new();
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struct pair result[input_sz] = {0};
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for(register size_t i= PREAMBLE;i<input_sz;i++)
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{
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calculate_deficits(&input[i-PREAMBLE], &def, input[i]);
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for(register size_t j=0;j<PREAMBLE;j++)
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{
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result[i].num = input[i];
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size_t idx;
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u64 us = input[(i-PREAMBLE)+j];
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if(!map_get(&def, us, &idx)) continue;
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u64 other = input[(i-PREAMBLE)+idx];
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// Found pair!
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result[i] = (struct pair){.valid = other!=us, .num=input[i], .sum = { us, other }};
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}
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map_clear(&def);
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}
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map_free(def);
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for(register size_t i=PREAMBLE;i<input_sz;i++)
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{
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if(!result[i].valid && !(result[i].sum[0] | result[i].sum[1])) {
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#ifdef PART2
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return find_set(result[i].num);
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#else
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printf("%lu\n", result[i].num);
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return 0;
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#endif
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}
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}
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fprintf(stderr, "Not found\n");
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return 1;
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}
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