How to validate Iranian 10 digits national code in Flutter (Dart)?
It has a specific pattern.
Following method is written in Dart based on this android code and is tested to validate Iranian National Code (Melli-Code) in Flutter:
bool validateNationalCode(String nc) {
if (nc.trim() == '') {
return false;
} else if (nc.length != 10) {
return false;
} else {
int sum = 0;
for (int i = 0; i < 9; i++) {
sum += int.parse(nc[i]) * (10 - i);
}
int lastDigit;
int divideRemaining = sum % 11;
if (divideRemaining < 2) {
lastDigit = divideRemaining;
} else {
lastDigit = 11 - (divideRemaining);
}
if (int.parse(nc[9]) == lastDigit) {
return true;
} else {
return false;
}
}
}
Related
My code failed on haystack = "hello", needle = "ll".
Expected: 2, my output: -1.
Here's my code:
class Solution {
public int strStr(String haystack, String needle) {
if (needle.length() == 0) {
return 0;
}
String result = "";
int i = 0;
int j = 0;
while (i < haystack.length() && j < needle.length()) {
if (haystack.charAt(i) == needle.charAt(j)) {
result += needle.charAt(j);
i++;
j++;
}
result = "";
i++;
}
if (result.equals(needle)) {
return i - needle.length();
}
return -1;
}
}
What did I miss?
Thank you!
class Solution {
public int strStr(String haystack, String needle) {
if (needle.length() == 0) {
return 0;
}
String result = "";
int i = 0;
int j = 0;
while (i < haystack.length() && j < needle.length()) {
if (haystack.charAt(i) == needle.charAt(j)) {
result += needle.charAt(j);
i++;
j++;
} else {
result = "";
i++;
}
}
if (result.equals(needle)) {
return i - needle.length();
}
return -1;
}
I think this is what you expect.
in your answer, when haystack.charAt(i) == needle.charAt(j) is okay, you add the needle.charAt(j) to result, and you set result empty string. That's why you are wrong.
so, in the end, the result is empty, and return -1;
I was trying to use the mod % operator in C++ but it shows the error Expression is not assignable
int i = 0;
cin>>i;
// for (i; i < 25; i++) {
if (i < 25 && i % 2 = 0) {
cout<<"test"<<i;
} else {
cout<<"test2"<<i;
}
}
return 0;
}
int i = 0;
cin>>i;
// for (i; i < 25; i++) {
if (i < 25 && i % 2 == 0) {
cout<<"test"<<i;
} else {
cout<<"test2"<<i;
}
}
return 0;
}
i%2=0 changed i%2==0
I want to make a falling sand simulation using cellular automata, but when I update it, nothing happens, and when I want to do a line of diffrent material using lineDrawing() this material appear in random cells. This is update code:
void update()
{
for (int i = verticalNumberOfCells - 1; i > 0; i--)
{
for (int j = 0; j < horizontalNumberOfCells; j++)
{
world[j][i].update(false);
}
}
for (int y = verticalNumberOfCells - 1; y > 0; y--)
{
for (int x = 0; x < horizontalNumberOfCells; x++)
{
if (world[x][y].hasMoved) continue;
if (world[x][y].state == 0 && world[x][y].state == 1) continue;
if (canMove(world[x][y].state, x, y + 1))
{
move(x, y, x, y + 1);
}
}
}
}
The auxiliary functions that I use to check if the contents of a cell can change and to change the contents of a cell look like this:
boolean canMove(int state, int positionX, int positionY)
{
if (positionX < 0 || positionX >= horizontalNumberOfCells || positionY < 0 || positionY >= verticalNumberOfCells) return false;
int otherSubstance = world[positionX][positionY].state;
if (state == 5) return (otherSubstance == 4);
if (otherSubstance == 0) return true;
if (state == 2 && otherSubstance == 3 && random(1f) < 0.5f) return true;
return false;
}
void move(int fromX, int fromY, int toX, int toY)
{
Cells otherSubstance = world[toX][toY];
world[toX][toY] = world[fromX][fromY];
world[fromX][fromY] = otherSubstance;
world[fromX][fromY].hasMoved = true;
world[toX][toY].hasMoved = true;
world[fromX][fromY].velocityX = 0;
world[fromX][fromY].velocityY = 0;
if (toX > fromX)
{
world[toX][toY].velocityX = 1;
} else if (toX < fromX)
{
world[toX][toY].velocityX = -1;
} else
{
world[toX][toY].velocityX = 0;
}
if (toY > fromY)
{
world[toX][toY].velocityY = 1;
} else if (toY < fromY)
{
world[toX][toY].velocityY = -1;
} else
{
world[toX][toY].velocityY = 0;
}
}
I was able to fix this problem. The thing was, copying a cell in the move function didn't work. Here is the wrong version of the code:
Cells otherSubstance = world[toX][toY];
world[toX][toY] = world[fromX][fromY];
world[fromX][fromY] = otherSubstance;
and here is right version of the code:
int oldState = world[toX][toY].state;
world[toX][toY].state = world[fromX][fromY].state;
world[fromX][fromY].state = oldState;
Can anybody explain what this code actually do and how it is re targeted the difficulty. I want my difficulty to be re targeted every 60 seconds, searching on internet find that this function will re targeted the difficulty.
I am working on Logos LGS coin.
unsigned int static KimotoGravityWell(const CBlockIndex* pindexLast, const CBlockHeader *pblock, uint64 TargetBlocksSpacingSeconds, uint64 PastBlocksMin, uint64 PastBlocksMax) {
/* current difficulty formula - kimoto gravity well */
const CBlockIndex *BlockLastSolved = pindexLast;
const CBlockIndex *BlockReading = pindexLast;
const CBlockHeader *BlockCreating = pblock;
BlockCreating = BlockCreating;
uint64 PastBlocksMass = 0;
int64 PastRateActualSeconds = 0;
int64 PastRateTargetSeconds = 0;
double PastRateAdjustmentRatio = double(1);
CBigNum PastDifficultyAverage;
CBigNum PastDifficultyAveragePrev;
double EventHorizonDeviation;
double EventHorizonDeviationFast;
double EventHorizonDeviationSlow;
if (BlockLastSolved == NULL || BlockLastSolved->nHeight == 0 || (uint64)BlockLastSolved->nHeight < PastBlocksMin) { return bnProofOfWorkLimit.GetCompact(); }
for (unsigned int i = 1; BlockReading && BlockReading->nHeight > 0; i++) {
if (PastBlocksMax > 0 && i > PastBlocksMax) { break; }
PastBlocksMass++;
if (i == 1) { PastDifficultyAverage.SetCompact(BlockReading->nBits); }
else { PastDifficultyAverage = ((CBigNum().SetCompact(BlockReading->nBits) - PastDifficultyAveragePrev) / i) + PastDifficultyAveragePrev; }
PastDifficultyAveragePrev = PastDifficultyAverage;
PastRateActualSeconds = BlockLastSolved->GetBlockTime() - BlockReading->GetBlockTime();
PastRateTargetSeconds = TargetBlocksSpacingSeconds * PastBlocksMass;
PastRateAdjustmentRatio = double(1);
if (PastRateActualSeconds < 0) { PastRateActualSeconds = 0; }
if (PastRateActualSeconds != 0 && PastRateTargetSeconds != 0) {
PastRateAdjustmentRatio = double(PastRateTargetSeconds) / double(PastRateActualSeconds);
}
EventHorizonDeviation = 1 + (0.7084 * pow((double(PastBlocksMass)/double(144)), -1.228));
EventHorizonDeviationFast = EventHorizonDeviation;
EventHorizonDeviationSlow = 1 / EventHorizonDeviation;
if (PastBlocksMass >= PastBlocksMin) {
if ((PastRateAdjustmentRatio <= EventHorizonDeviationSlow) || (PastRateAdjustmentRatio >= EventHorizonDeviationFast)) { assert(BlockReading); break; }
}
if (BlockReading->pprev == NULL) { assert(BlockReading); break; }
BlockReading = BlockReading->pprev;
}
CBigNum bnNew(PastDifficultyAverage);
if (PastRateActualSeconds != 0 && PastRateTargetSeconds != 0) {
bnNew *= PastRateActualSeconds;
bnNew /= PastRateTargetSeconds;
}
if (bnNew > bnProofOfWorkLimit) { bnNew = bnProofOfWorkLimit; }
return bnNew.GetCompact();
}
Well, I am dealing with sudoku solving algorithm and generation but stuck at rather simple task. I have made the check, whether a number is really fit in the position row-wise and column-wise. But what it is driving me mad is block check, ie, whether the number is really fit in the 3x3 block.
It must be simple enough but I can't really arrive at the solution. In short, I want to know the 3x3 block to which a position in matrix belongs. Here are some of the assert cases. The block no, row no and col no indexing starts from 0.
assert("x( 0, 8 ) === 2");
assert("x( 8, 8 ) === 8");
assert("x( 3, 3 ) === 4");
assert("x( 3, 7 ) === 5");
assert("x( 7, 1 ) === 6");
x( i , j ) returns the block number where i = row and j = col.
Isn't it just:
block = 3 * (i / 3) + (j / 3)
(assumes integer operations).
I would code a check, something like this (in pseudo C++)
// row = row to check
// col = column to check
// checkNum = number we are thinking of inserting
bool check(int row, int col, int checkNum)
{
int blockRow = 3 * (row/3);
int blockCol = 3 * (col/3);
for(int i = 0 ; i < 9 ; i++)
{
if(grid[row][i] == checkNum) return false; // number exists in the row.
if(grid[i][col] == checkNum) return false; // number exists in the col.
if(grid[blockRow + i/3][blockCol + i%3] == checkNum) return false; // number exists in the block.
}
return true;
}
Here is a sudoku solver in javascript. Taken from DSSudokuSolver, that I created.
The CleanElements function does something similar to what you are asking for.
CleanElements = function(comp_ary, Qsudoku){
for(i=0; i<9; i++){
for(j=0; j<9; j++){
/*if(Qsudoku[i][j] != ""){
comp_ary[i][j]=[];
}*/
for(k=0; k<9; k++){
i_index = comp_ary[i][k].indexOf(Qsudoku[i][j]);
if(i_index != -1){
comp_ary[i][k].splice(i_index, 1);
}
j_index = comp_ary[k][j].indexOf(Qsudoku[i][j]);
if(j_index != -1){
comp_ary[k][j].splice(j_index, 1);
}
}
if(i < 3){
i_min = 0;
i_max = 2;
}
else if(i < 6){
i_min = 3;
i_max = 5;
}
else{
i_min = 6;
i_max = 8;
}
if(j < 3){
j_min = 0;
j_max = 2;
}
else if(j < 6){
j_min = 3;
j_max = 5;
}
else{
j_min = 6;
j_max = 8;
}
for(i_box=i_min; i_box<=i_max; i_box++){
for(j_box=j_min; j_box<=j_max; j_box++){
index = comp_ary[i_box][j_box].indexOf(Qsudoku[i][j]);
if(index != -1){
comp_ary[i_box][j_box].splice(index, 1);
}
}
}
}
}
return comp_ary;
}
FindElements = function(comp_ary, Qsudoku){
for(i=0; i<9; i++){
for(j=0; j<9; j++){
if(comp_ary[i][j].length == 1){
if (Qsudoku[i][j] == ""){
Qsudoku[i][j] = comp_ary[i][j][0];
comp_ary[i][j] = [];
}
}
}
}
return Qsudoku;
}
IsThereNullElement = function(Qsudoku){
for(i=0; i<9; i++){
for(j=0; j<9; j++){
if(Qsudoku[i][j] == ""){
return false;
}
}
}
return true;
}
InitEmptyArray = function(){
empty_ary = Array();
for(i=0; i<9; i++){
empty_ary[i] = Array();
for(j=0; j<9; j++){
empty_ary[i][j] = Array();
for(k=0; k<9; k++){
empty_ary[i][j][k] = (k+1).toString();
}
}
}
return empty_ary;
}
DSSolve = function(Qsudoku){
comp_ary = InitEmptyArray(); //Complementary Array
window.comp_ary_old = comp_ary;
IterationMax = 5000;
while(true){
IterationMax -= 1;
comp_ary = CleanElements(comp_ary, Qsudoku);
console.log(comp_ary);
if(window.comp_ary_old == comp_ary){
//implement this.
}
else{
window.comp_ary_old = comp_ary;
}
Qsudoku = FindElements(comp_ary, Qsudoku);
//console.log(Qsudoku);
if(IsThereNullElement(Qsudoku)){
return Qsudoku;
}
if(IterationMax == 0){
return null;
}
}
}