49 lines
724 B
C++
49 lines
724 B
C++
#include "stdafx.h"
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#include "rangeop.h"
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RangeOp::RangeOp(int size) {
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nn = 1;
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while(nn < size) {
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nn *= 2;
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}
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vals = new int[2*nn];
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memset(vals, 0, 2*nn*sizeof(int));
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}
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RangeOp::~RangeOp() {
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delete[] vals;
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}
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int RangeOp::get(int pos) {
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return vals[nn + pos];
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}
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void RangeOp::set(int pos, int amt) {
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add(pos, amt-get(pos));
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}
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void RangeOp::add(int pos, int amt) {
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for(int s=nn; s>0; s/=2) {
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vals[s + pos] += amt;
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pos /= 2;
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}
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}
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int RangeOp::get(int start, int end) {
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int ret = 0;
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int i;
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for(i=1; start+i<=end; i*=2) {
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if(start & i) {
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ret += vals[nn/i + start/i];
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start += i;
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}
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}
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while(i) {
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if(start+i <= end) {
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ret += vals[nn/i + start/i];
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start += i;
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}
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i /= 2;
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}
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return ret;
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} |